So after the last competitive game I played, where I locked Torb, two other people ALSO locked Torb, and yet I was the only one to build a turret that actually lasted more than thirty seconds, I have decided to write a very quick guide on how to actually play Torbjorn, because apparently nobody knows.
Here it is. Put your turret in the following place:
1) A little bit behind where your team is fighting, because the turret does not do enough damage to kill enemies on its own. You need enemies to be focused on something else when the turret is hitting them. That means the turret can't be on the point by itself while your whole team plays forward -- it needs to be overlooking your team while they fight. However, you can't set up the turret under fire, so you need to put it a little bit back so that when your team falls back the enemies will run past it chasing them.
2) Just inside a doorway, in a corner, or otherwise in a position where the enemy has no long-range line of sight to it. I see a huge number of Torbjorns put their turret in the center of something or on top of something. This is always wrong. I can only assume they do it because they main somebody like Tracer and they think the turret is a TF2 god-cannon. It is not. The ideal position for your turret is actually in a place where it will only start shooting when your enemies have run past it, which you can accomplish by angling its placement in a doorway to occlude more lines of sight.
3) Not in the same place it was when it got blown up. Easy one! Your enemy keeps losing vision and then coming onto the point assuming things haven't changed. So change things. If your turret died you should definitely move it so that they have to rearrange their attack pattern. Even if it doesn't die, if you have some time, it's worth considering just moving it somewhere else that follows rules 1 and 2.
That's it. Put the turret in the right place, don't try to heal it, just go click on people. Torbjorn is half turret and the turret is 75% location so don't be 5/8s of a character.
(Last pro tip: if you have ult, but your turret has been destroyed, you can place a turret, ult, switch to hammer and upgrade the turret at super speed. This is occasionally worth doing.)
