ori jungle is quite weak in early game, so dont pick her if the ennemy jungler is a counterjungle champ like lee or rengo.
Ori is quite good in your team if your teammates have a lot of cc, because you dont have much of it, except your ult and your w
dont pick her if the ennemy team has much burst, because you are gonna die hard if they see you coming.

Ori jungle is a way more better last pick than first pick

oris aa damage is quite huge and she synergyzes quite well with items like whits end and rageblade. also the sheen proc can be quite nice on her.
as you are ganking, just try to land some aa while using your skills and its gg

if you are getting invaded, or someone steals your blue at the beginning, you wont really get into the game soon.
you are quite vulnerable, so you need to place wards and your team should do the same.
also, ori is quite complicated in question of positioning, so dont play her in the jungle the first time you play ori.