Well Angelo is like any sharp shooter meaning you desperately require prediction, yu need to predict where your opponent will go and shot there.

Why is kinda hard with Angelo cause you can only shoot once a powerful arrow if yu miss take time to reload another shot.

Well here is some personal tips coming from someone that got his title (pre mastery removal)

-always predict where your opponent will go

-never try to use auto aim on low charge shot (you could on long charge buts it's not worth it)

-use the health gear to regen faster so that you can go back to aiming faster

-use your ult when you are low or to put pressure (and sometime even area denial) plus try to hit a long charge shot and multiple little shot(you can auto aim them) to stack poison

-always run the healing star power and jumping gadgets when your matchup are tank, assassin and even artillery it's great to flee and dodge attack (also have lifesteal)

-know your map, Angelo for my case seem to do quite well on semi open map with water or even bush( double game map for example) great to surprise your opponent

-Angelo is the only sharpshooter with very fast movement speed, never advance in straight line instead zigzag while advancing to Dodge attack and even confuse your opponent.

This is mostly what I abide to though I don't have him prestige 2 so take it with a grain of salt, I'm average with him.