Hello my friends. This is my Jax build.
The first build named "Jungle" build is the one i usually play when playing Jax.
My item choice is a bit different.
I find that Jax is a lot squishier than he used to be. So i start of building him with a trinity force for the increased... everything. Then i go for a Dmg/Tank item like Crystal Scepter.
Now when i have a little survivability my death should hopefully have stayed at 0 :p.
Now time to eliminate the enemy team! i now go for full dmg focusing on my ULT passive.
Meaning i scale more AP than AD in my build when going for dmg.

If your game isn't going so well try buying
Lich Bane instead of Rabadons.
Guardian Angel instead of Rageblade or a Hextech drinker

Tips.
1. Make sure you always have a sight ward in your inventory. Including your Lantern.
A little trick i did to be swift with my ward escapes are keybinding my item slot 4 to my mouse button 4 (On the left side of my mouse)'
2. If you can, try to get your 8/6 stacks of attack speed up before engaging in a fight.
3. DON'T forget your Gunblades active!! its very good if some one is escaping and your Q is on CD + it's good for last hitting from a distance.
4. When ganking, if you see that the enemy has flash as a summoner spell DON'T jump on them directly with your Q because they will flash away. Try using your ghost to run in range from the bush and then deal some dmg. When they now flash away use your E and jump on them and stun.
5. With the right runes you should be able to solo dragon at lvl 7. It can be a game changer if you keep time on dragon through out the entire game making sure you take it all the time.