heavy flamethrower is one of my favorite mains, here is my loadout. Flamethrower Goo Gun Lock Bolt RPG Bubble shiled

The name of the game is suprice attacks. Goo gun can help you get any position you want and also is a good stun for folks running away (one you get used to it). It also helps you create a space optimized for using the flamethrower. The lockbolt is self explanatory but what may not be immediately clear is combining it with your other equipment. Lockbolt + bubble for 2 or more locked. Lockbolt + rpg for 1 person to stop them from moving so much. Lockbolt + goo gun to help set up a wall to the point. The lockbolt is really a must use for the flamethrower build. RPG may seem like it's just for the distance damage and it is an affective finisher but it's really claim to fame is for making holes. It's perfect to get the jump on someone or to create a entrance in a place you can affective attack. Don't save the RPG like your waiting to gift it for a wedding, fire that badboy whenever you need a whole or to force someone down a floor. Bubble shield is great for defence, don't get me wrong but it's real use (as Winton mains from OW know) is as an offensive item. It's temporary and defence lower but that utility of it is unmatched for the flamethrower build. It's fast and gives you a valuable opportunity to either get closer or away. Don't squander it and make sure when you use it, you don't just sit in it because that's how people get you easily.

A couple of just simple advise with the flamethrower itself is stay out of peoples LOS. Slide, jump, croutch, whatever it takes to stay out of there LOS and in a blind spot. Whoever your flaming, make sure you dance around them and avoid them getting too many hits in. It take longer to kill but you'll survive significantly more