there is 3 easy combos with Xayah:
-QAAE for activate the E stun
-R-flash for replace you
-W before QAAE to deal more damage

Xayah is pretty good in early so you can try some trades but stay safe anyway if you dont feel it.

I really like to play with this build when i know that the enemy compo allow me to snowball.
Critical shot work pretty well against a team without huge burst and not too much cc.
When you are fed it's becoming easy to play objectives without any pressure, of course only if your team play around you.