Firstly I recommend dorans shield cuz u need to live until lvl 3 so u can get all three skills to do jaxs comboes.Second take ninja tabi too redcue the dmg u take.Then take hextech gunblade so u can deal tones of dmg.The most important thing u have to know about jax is that u must kill first the ad carry of the team so ur team will win the teamfight.This work is easy to be done buy jax so u have to buy some life amd dmg.Then buy trinity force and warmogs armor.Then buy banishee's veil to block the spells in teamfight and kill easier the ad carry.