When playng the pyro, you should always consider that the flametrower got very short range. The shotgun is a good solution to this problem. Noone wants to go near a enemy pyro, and thus they keep their distance. Then you use your shotgun and blow em full of holes. Then you move so that they are being forced into a corner, before you either burn em to ashes, chop em up to haggis, or just simply kill them with your shotgun. If you use the flare gun, you should move so that the flare hit the enemy, and then you retreat. A burning enemy will seek a medic or a medpack fairly fast, and you can use this to close in the distance, or you can lure him after you, and then ambush him with the backburner. If you use the axestinguisher then you can use the flare gun to light him up and then finsih the job with a quick slash.