I watched a documentary about Sun Tzu's "Art of War". It went into the book and showed how it can be applied to games like this and in war. From it, I've gathered some steps and tips that helped me win. However, if not implemented, a loss is almost guaranteed (which I've experienced many times).

STEPS
1. Get power-ups as fast as you can by placing bombs steadily and accordingly (don't place them where you'll be trapped yourself, don't place them too quickly). If none come your way, then focus on dodging as many attacks as possible to gain a lot of range when the board begins opening up (crates are destroyed). This is where reflexes come to play, even if you experience lag. (Sun Tzu's preparation and quick-thinking is implemented. NEVER plant bombs before you're ready to strike). The killing will begin if you have enough upgrades (see step 2).

2. Once you have full upgrades for bomb and speed AND have at least 6 range in your blasts, place your bombs where it can target the most people and still exclude yourself. For example, placing a bomb at a clear cross intersection is much more effective than placing it at a dead end (Sun Tzu always says no to random placements of weaponry and says yes to careful placement). Like what other posters say, try L formations or + formations and connect the bomb's range of attack to maximize range.

STEPS/TIPS
3. Never lose morale. Morale is key to victory. If you give up easily early on, then you'll definitely lose. You technically have a chance to come back if you die and are only down by 1 point at the very start. Just revive quickly and focus on implementing steps 1 and 2. (Sun-Tzu knows that having the will to win is key).

4. Don't get distracted by ANYTHING. The points, the jumping audience, people messaging you, NOTHING should distract you from winning. You can do all that while you're dead. (Sun-Tzu always promoted distracting the enemies with decoys, so don't get distracted by them yourself). Being distracted leads to greater chances of death by a bomb with a large range.

5. Luck always plays a role in winning, from receiving an AFKer that gets kicked to striking on other people's mistakes to other people having lag issues. If you don't take those chances, it'll be the difference between 1st and 3rd. (Sun-Tzu: take your chances by considering people's weakness and strike at will).

TIPS:
1. Ensure that you can complete Step 1 in 2 minutes. You will almost always lose if you don't.
2. When you see bombs, assume that it has maximum range (15). Don't take chances by standing in its line of fire; you don't know how far the bomb can go. Hide away from it and come out after the blasts.
3. Ensure that you can begin a wide-spread chain reaction when setting your bombs. It will complete Step 2 most efficiently.
4. Make sure you can trap the other player in a corner with your bomb at the early stages without endangering your life. It's a way to gain early points while you're still upgrading (from other people's posts).

It's a very long post, but there's a lot you gotta do to get good at blast. Just like how many things in this world need work for continuation. I'm a blast veteran. I've faced many blast network greats and beat them, although I do have my bad days ;_;