There are, of course, some exceptions to the claim in the title. Jelly King is the big one, of course, and sometimes it's worth taking a hit to assassinate a healer in a crowd of mobs.
But I'm not here to talk about the exceptions. In most battles, you're not supposed to get hit. You're supposed to kill the mobs without taking any damage yourself.
I suspect that a lot of players come from games where that's not the case. If you play WoW, for example, then you're supposed to get hit some. If you're a tank, then you're really supposed to get hit a lot. You can't dodge or block there like you can here. While the game does have concepts that it calls dodging and blocking, they're totally different from what you can do in this game.
But here, a lot of players act like you're supposed to charge in, attack recklessly, and trade hits with mobs. The top levels are more forgiving of blunders, and will let you get away with this. Deeper levels are less forgiving, and if you're only hitting mobs five times as often as they're hitting you, then you're in deep trouble.
This raises the question of, how do you kill mobs without getting hit? You get two main tools to avoid getting hit: blocking and dodging. And you need both.
Blocking is simple enough. Use your shield before something is going to hit you, and the shield will block it so that you take no damage. But you can only block so much, and if you try to block everything, mobs will wear down your shield and you'll take damage anyway. Blocking is mainly a backup measure for when you can't dodge everything.
The more important thing is dodging. That is, get out of the way. Mobs won't lead you. Most attacks only go straight at you, and in a straight line, or perhaps rather, sometimes several straight lines from a single attack. Move out of that line while a mob attacks and you won't get hit.
If you run toward a teammate, then sometimes an attack meant for that teammate will hit you instead. If you run toward open space, you're usually much safer. If a lot of mobs attack where you were 1-2 seconds ago but none attack where you are now, then you don't get hit.
Dodging and blocking are not mutually exclusive. If you can probably dodge a given attack while at the reduced movement speed of blocking, it doesn't hurt to block while you're doing so. This is especially the case for dodging gun puppies. You probably dodge, and if you mess up, then you block the attack instead and still don't take damage.
If all you do is block and dodge, then mobs won't die. The trick is to attack when mobs aren't. The key is to notice that mobs don't attack very quickly. Right after a mob attacks, it can't attack again for a while. Thus, you don't need to block or dodge while the mob isn't attacking, and that's your chance to get in attacks of your own.
There are three types of weapons in this game, and you need all three. A lot of people seem to use swords exclusively. Some also use guns at times, but relatively few use bombs at all. There are situations where each is necessary, and the others don't work very well. If you don't carry at least one of each type of weapon, you're doing it wrong.
Guns are great against mobs that move slowly. Most constructs fit in this category, for example. Guns are especially good against gun puppies, which don't move at all. Guns are also great against slow melee mobs such as lumbers. If you never get into melee range, the mob can never hurt you. Guns don't work as well against small mobs that can dart around quickly and will dodge most of your shots, such as devilites.
Bombs are ideal against groups of mobs that follow you around. You can keep running and constantly dodging while the bomb charges, without having to stop to get near the mobs and attack. You drop a bomb, then mobs chase you into the bomb's radius and take damage. Then you charge up another bomb.
For a single mob, this is slow. The great thing about bombs is that you can hit several mobs at once. If there are too many mobs for you to dodge them all individually, just keep running to open space and you can often avoid getting hit at all. Meanwhile, when you lay a bomb, you might hit six mobs at once. Soloing an arena is good practice at this.
Swords are good for small groups of mobs that dart around quickly, making them hard to hit with a gun. Swords are also good for when you need to do a bunch of damage in a hurry, especially to assassinate a healer. Most people use swords in the situations where they should, so I don't think too much needs to be said here.
But a lot of people who do use swords don't use them properly. Once you get into melee range, you're not supposed to just attack, attack, attack, and hope that the mob dies before you do. Attack until mobs are ready to counterattack, and then get out of there before they do.
Sometimes this means that you can't finish your three hit combo. While the third hit does do extra damage, it's better to hit the mob twice and not get hit yourself than to hit it three times and then get hit in return. Different mobs have different attack rates, and you'll learn by experience how many attacks you can sneak in with various types of mobs before you need to back off.
Some mobs have conspicuous actions that warn you when they're about to attack. Wolvers and greavers do this well in advance, and their warning looks to me like trying to charge something up. When a kat darts around, that means it's about to attack. Some others give a little less warning, but still in plenty of time to do something about it. When a mob is about to attack, that means it's time to lay off attacking yourself, and dodge or block the attack instead.
There's no rule that you have to strike first. Sometimes it works better to let mobs burn their attacks, and then you counterattack while they're waiting for their attacks to recharge. This is most commonly useful with groups of mobs, when you aren't necessarily certain which mobs have attacked recently and which haven't.
Another thing that often works nicely is attacking a mob from behind while it attacks someone else. Most mobs can't attack you if you're behind them, so you can hack away safely until the mob turns around.
Where you fight can often matter, too. There's rarely a need to fight in an area laden with spikes or condition traps. Most mobs can readily be pulled away from them, and fought more safely elsewhere. It's also pretty easy to blow up exploding blocks from a distance before beginning a fight in earnest, so that you don't have to worry about detonating them on you in the middle of battle.
Practice at the game is supposed to make you better at it. But if you're not even trying to do things the right way, all that practice gets you is experience at playing badly. That doesn't lead to becoming good at the game, but it seems to be the situation that a lot of people are in.
A lot of players probably already knew everything that I said in this thread. But many don't, or at least play like they don't. "The charge of the light brigade" is not a good strategy, but many players employ it in every single battle. The title of this thread is really addressed at them.
probably needs to go in the new recruits forum