You should clarify that you're looking for LD tips for gunning, not so much PvE.

Anyway:
I'm assuming a you are a gunner striker in LD

1-What gears should i wear? And explain why i should wear this gear.
Shadowsun set is good. You want that vh damage.
Get two penta trinkets. I noticed you didn't mention what you had trinket wise.
How many weapons will you be using?

I would rank your guns like this:
1) storm driver. I would try to get asi med on it, but it's not a big thing.
2) AP or Sent, both have the same ASI, so pick one, but not both. Sent for the shadow damage since it's different from the storm driver
3) Polaris for it's defensive use, but don't use it as a main since you will never learn to gun properly with it.

And that's it. The rest are useless in LD. Don't make a callahan/iron slug for ld, the lack of movement is too annoying. It's awesome when you get a few kills off, but it just doesn't work well. I've tried using it, I really have.
Blitz - same as above, but even worse.

2-Should I pick a bomb & sword with me?
I have an good asi toothpick that I carry with me because I also play clone striker, but this is not necessary. It's good for when someone is close to you and it just makes sense to fight them with a sword. It also messes people up since they don't expect a gunslinger to be attacking them with a sword.
Bombs seem like fun, but if you're a striker, so the charge time penalty will kill it.

3-Whats the tactics of dodging & interrupting attacks?
This is the important part.
Shoot from afar, a striker will zoom up to you, move away before they get to you and shoot them (before they even get to the spot, since you need to consider bullet travel time.) This is called kiting.
In a lag free environment, you just need to aim where you were and usually you'd hit them. Depending on your lag (and gun), you will need to shoot a little ahead of them.

The best weapon to use for kiting is a driver. You shoot once, dash, shoot again, dash. The goal is to not get hit, and keep harassing them. Bonus points if your storm driver shocks them.
You can kite with the sent, but it doesn't seem as effective, maybe the hit boxes seem too small, or there are no lucky ricochets in tight places to help get hits.
You can kite with the polaris, it's fun, but it's a different way to kite. I wouldn't recommend it since skilled people can read it more easily.

Sometimes you will kite multiple people. this is a good thing. Even if you can't kill them all, it means you have now given your team the advantage somewhere else in the map.

You will run out of striker boost eventually. If you do things right, the enemy should run out before you, so this hopefully isn't to your detriment, but sometimes it can't be avoided. Just shoot with a polaris or sent to keep the enemy away. Don't use the driver since the low number of shots puts your to a disadvantage.

4-Should i craft a Hail driver?
Only if you have CTR. The storm driver is better because of shock. Frozen targets break freeze if hit again and a hail driver won't freeze many times in a row unless you're using a charge.

5-How to shoot accurate to moving enemies? Bullet hits enemis to compensate for lag, but nothing happens.
I touched on this above, you need to shoot infront of them (play in the future.)

While your bullet is traveling to them, they are moving on their own computer. By the time the info gets to the server, the bullets hits where they have moved past, resulting in a miss. You only see it as a hit because your graphics are a bit behind the server, but it doesn't count as a hit. The opponent sees you as just missing them.

1-What gears should i wear? And explain why i should wear this gear.
If you're striker:
Shadowsun set/ 1 Gun damage trinket/1 heart trinket/ ASI on guns if possible.
Striker gunners are all about kiting, so you want to make sure that when you poke in a hit, it hurts.

Though this isn't what you asked for, if you're a recon:
Justifier set/2 gun damage trinkets (lol, my armor/trinket sets) ----- or ----- Shadowsun set/1 Gun damage trinket/CTR or ASI trinket/ASI on guns if possible.
Recon gunners are either about sniping people down with charge attacks, or assassinating people with statuses. Heart trinkets are an absolute waste for recons.

As for kiting weapons: these are good guns for kiting:
- Valiance - the knockback/2 bullets/bullet speed all work well for slowing down people who are after you. I'm surprised nobody's mentioned this.

- Any of the status drivers (Magma has use for this especially since it does damage while you're moving, too; Storm is good if you're actively trying to kill quickly; Cryo is good if you're trying to hold off multiple people and need to worry about less people at a time)

2-Should I pick a bomb & sword with me?
Bomb, no, not if you're striker. Sword is a possibility though, since striker at least gets some bonuses for swords. If I carry a heavy sword, it's for hitting people who are bunched up since guns can't hit all of them at the same time.

5-How to shoot accurate to moving players? Bullet hits enemies in visual, but nothing happens.
Because of latency, you have to know to "miss" ahead of your opponent in order to actually register a hit. If they're recon or guardian, and moving sideways, try shooting so your shot hits a tile or so IN FRONT of them (this is different from shooting ahead so the bullet reaches the point at the same time - I'm talking about actually "missing" in your screen).

4-Should i craft a Hail driver?
I personally want to make one, but I feel like it's more of a recon gun (charge bonuses) or hybrid sidearm (stopping an enemy so you can hit them with a stronger attack from a sword).

3-Whats the tactics of dodging & interrupting attacks?
Dodging and interrupting, at its base, comes from you being able to predict your opponent and being able to aim. This is the core of gunner gameplay.

Just some low-level examples: people expect you to move away from them and move towards you. They will gain distance if you shoot and miss, but you can interrupt and get multiple shots in if you do hit. Alternatively, you can switch directions and move TOWARDS them while they're in the mindset of moving forward - it gains more distance if they have slower reflexes, since both of you are moving in opposite directions. Basically, predict and be unpredictable.

As far as interrupting, you need to 1) have a good understanding of how to aim with latency and 2) understand invincibility frames.
- Aiming with latency in mind is knowing how to aim. Get used to it.
- Because of invincibility frames, you will need to pause a little bit between shots if you want each shot to register for damage. If you attack too quickly, you waste a shot, and that delay makes your DPS slower in the long run.

Now, if you have a Blaster or Antigua line, here's another concept you might want to think about: the range of possible places your opponent might move into. Here's an example-

Say you're playing vs a melee striker - imagine a triangle extending from you to where your enemy is:
http://i.imgur.com/9wOXg.png

In that range is the possible areas the enemy might move to hit you. So pretty much, any shot in that range has a good chance of hitting. Now put yourself in the striker's shoes - you know you're approaching a gunner, so if it's a matter of moving in a straight line, the gunner will hit you first - so how do you avoid it? You move to the side.

Put it together with you as the gunner - you've essentially eliminated the chance that they will move DIRECTLY towards you, so the striker may either:
- Move in a wide arc to make you miss.
- Move towards you, but a little bit from the side.

If they move in a wide arc, they're just wasting their boost and you can move away to gain distance, so you don't necessarily lose anything, so that's not really a problem.

The problem is if they move towards you, so you want to try to "block off" those movements - that is, you "spray" bullets towards the edges of the triangle, predicting they will move along that area. In the image, it's a smaller cone of danger (actually it's probably wider than that in reality), but the closer they get, the wider it gets. The widest/most unpredictable/hardest situations to hit are when they're in close range, because if you take into account latency and bullet speed, they can actually be behind you when you're shooting in front. That's where your own skill and prediction have to come into play.

With blaster and antigua lines, you can shoot 2 bullets quickly without reloading, so you have a higher chance of covering those possible movements.

If/when you do land a hit, it slows them down/stops their boost, and that's when you have to try to 'combo' them without accidentally landing a hit while they're invincible and without missing.

That took a lot of words, but in all honesty, that's even a more watered down example than reality. In reality, you're not just standing in place, but you can move, and if they chase you, you just have to worry about blocking off their chasing path.
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Anyway, take some of that with a grain of salt - I don't/can't play striker LOL.
I play recon, where getting hit while you're shielding means death, and you don't have the ability to run. It's kill or be-killed with no escape for me XD

"Recon gunners are either about sniping people down with charge attacks, or assassinating people with statuses. Heart trinkets are an absolute waste for recons."

He also said he can't really provide Striker-specific advice, so. :P

All the guns are pretty good I think. I have loadouts with them all - exception being Nova (just never a need for it...) and Iron Slug. Callahan i use in combo with a hail driver only - that gun is suicide :). Just be sure to have a mix of speeds with your bullets. ATM I'm favoring Valiance, Umbra, and Biohazard.

For trinkets - max damage or extra health? Depends on how close you tend to get to the enemy.. how often you go solo.. your dodging skill... how well you can read players... I try both, but lean on my damage more then health. Just works well on my end.

You'll also see a lot of gunners using speed-alchemer shooting. It's not my style, but it certainly works for a lot of people. Spectate some gunners and get some ideas. There's a wide variety of effective weapons as opposed to the swordie (toothpick + DA/GF).

Though some people skilled with brandish style fighting are starting to pop up... props to them!

Just a bit of warning - you will die a lot. Like, a lot... before you get used to it. Big learning curve, but fun in the end.

@Little-Juances, That's one of the reasons to bring a Valiance. The Valiance fires a bullet as soon a you press attack so even if you are being interrupted, you can put out shots.

...but I can tell you, that Valiance does some sick damage. I go down in 5 shots from Blueflood's Max Damage (most likely, I assume he's got a heart trink) Valiance, and if the enemy is deathmarked or wearing Dragon Scale, they'll be hit hard. Plus, it might save your life by pushing a swordsman back just enough to put him out of range.

Aside from that, Polaris is effective if you're feeling lazy (I DESPISE the dang thing when it's used against me, that's all the info you need), as are the drivers and Callahan, and that freakin' Sentenza (or AP, most bombers have Elemental Defense while Gunners either have Elemental (Seerus and Nameless) or, more often, Shadow (Shadowsun). Both work on Skolvers, and Vogs and Snarbies appear at about the same frequency as each other.) Storm Driver, in particular, is great; as if Shock weren't annoying enough, I heard somewhere that players don't have invincibility frames during Shock spasms. If this is true, that means your Storm Driver charge MIGHT multi-hit with the ricochet, for massive damage. Magma is good for hit-and-run, Hail isn't half bad, and Nova and Umbra are good for straight damage.

If they ever get rid of those stupid Invincibility Frames again, Blitz Needle and even Volcanic Pepperbox will be incredible for sniping, and possibly for holding a chokepoint (imagine syncing Blitz charges in a narrow passage, it'd be NUTS), but right now it's not that great. VPepper will have some utility as a leaf blower if Invincibility Frames were removed.

Ask Tsubasa-No-Me about the Iron Slug. I hear she's used either the charge or one of the normal clip for interruption, but I'm not sure which!

If your computer can handle standing in a bomber's bombs, STAND IN THEM. Don't put standing in them over dodging enemy attacks, but it's better to stay where Skolvers fear to tread.

A striking Gunner needs to keep moving; it might be a good idea to carry a utility sword like the Freakin' Flourish or the Gran Frustration (Those are just weapon nicknames from a Bomber, mind). A recon Gunner needs to be unpredictable, and it might be good to pack an escape bomb like Shivermist Buster or Electron Vortex; the Recon Cloak, combined with a level 10 bomb, maxes Charge Time Reduction on the bomb. Vortex might help you escape if you place it behind you, though it slows you down when you charge it, while Shivermist can freeze non-resistant foes in place for you to unload that Storm Driver charge.

Valiance is very strong and stupid easy to use. Best at max range. Antiguas fill the same role, but aren't quite as good imo.

Alchemers take awhile to learn to use effectively, but will almost certainly be your main weapon. Use at close to mid range. Bring two and swap shoot if you like spamming, or for taking down guardian shields. It really doesn't matter which ones you use.

I don't use health trinkets. Most gunners use one.

As for strategy...try and get people to chase you. It's the easiest way of "controlling" your opponent's movement, which makes landing shots much easier.