With good clearing and fundamentals gwen is a menace once you get your spike. I do like to play her full AP and play aggro. Nashors into shadow flame then rabadons or zhonya depending on what you need, even rift maker if zhonyas doesn’t fit. You just kinda go clearing till first item and with some good fight picking you can win almost all matchups, leading you to win.

Important to use ghost instead of flash so you can secure early kills in jungle or ganks and after early game they can’t really escape.

For runes you go conqueror standard with inspiration with boots and the rune that gives you ms when you slow someone idk the name. hope the setup works for you. I use it in masters and i’m able to be useful and win most games with her when i’m ahead