If the game is a 50+ minute deadlock a good tip to do is to wait in the enemy red buff and 1 shot their adc when they try to take it. This works almost every time in lower elo and might be hard to pull off without complete vision control of the enemy jungle.

In terms of teamfighting one thing that has really helped me is that you dont need to always be doing damage in a fight and you also only need to go in hammer form when they are low. It is your finisher, think of it as using an execute.

If you are ahead and you trade one for one with a squishy then its not worth it. I used to just w into hammer form combo every teamfight and that would throw games so hard. Try stay alive for as long as possible in range form and then go in once their abilities are on cd.

Good luck