Number one tip: DO NOT ULT just for the hell of it. do it in team fights, when you’re close by. It triggers me so hard when fortress user’s just ult from miles away.
Also, if your team has one useless hero, Go full aggressive support build. If you have a good team comp, then go team support build. I would stick with the recommended builds.
if you have a good aggressive jungler… follow. This is the one captain that benefits from staying together. Fortress and Koshka early game is a seriously unstoppable force. Gank for days.
Their play style is very similar, need to be aggressive and need to dive, invade, start jungle camps and NOT take it. FEED your team and buff them to levels above everyone else.
Do NOT try to clear creeps on your own. You are the slowest minion clear speed in the whole game. Just soak up ambient gold should be enough. Just keep map awareness and ping where you want each hero to go.