First of all Jax is not a OP character. He is hard to play at early game but if you learn him you can control the game. If you feed the enemy team you can't turn back into game because the enemy team will always want to focus on you. You will be their source. At 3v3 Jax is a very powerful character. Probably one of the best. At 5v5 he is not bad at all, if you know how to play with him.

Jax is a very item depandent character. He has 2 MUST have items.
1-Guinsoo's Rageblade
Jax needs AP and also AD and this item gives you both. This item's passive is also very usefull. It gives you attack speed and ability power. Stacks up to 8.
2-Hextech Gunblade
Excellent item for Jax. Great AP and AD also lifesteal and spell vamp. OMG really good item :D. Nothing to say just buy it.
I tried emblem of valor for Jax. And I find this item pretty good. It gives you a bit lifesteal. And this is enough for Jax because of his attack speed you gain hp very fast.

Ghost: Very good spell for chasing and running. Usefull against fast champs.

Flash: I don't think that this spell is important for Jax. Just using it to escape. I don't recommend it.

Exhaust: This spell is must have. You can chase nearly every champ. Exhaust-ignite or exhaust-ghost is very effective.

Ignite: You can use this spell as a finisher. Using this skill with exhaust is a great combo.

Pros

-Great chaser
-Great farmer
-Not bad at jungling
-Great at 1v1
-Can solo Baron Nashsor :D

Cons

-Dying fast at teambattles
-Play cautious
-Don't be greedy
-Very item depandent

Farming is not a problem for Jax. He can farm easily with his ultimate at 6 level. But you need to be careful at the beginning of the game. You should make the last hit to the creeps, do not try to tank them. After 6 level farming will be very easy because of your ultimate's passive skill. Your every third attack makes huge damage and it also gives you attack speed. After buying Guinsoo's Rageblade probably he is the most effective character against creeps. His attack speed makes him very powerful. And with your "counter strike" skill you can give AOE.

The most important thing is do not start battles that you can't win. And do not always try to save your teammates life you can die so easily. If they feed you you are like unstoppable. Just try to have fun. Patches changed him a lot. Try the build and see the results.


Please give me some feedback. Just let me know what have I done wrong or right!

Thank you for reading, have fun :)