It´s my first guide, so I hope that it´s ok when some mistakes are there.
And I apologize that I didn´t make so much Chapters.

+ good getclose (Q,E) -- Q and E have long cooldowns
+ can escape good with Q -- passive have a long cooldown
+ late you get so much life with attacks (W and items) -- eary-game life peoblems

Go on offtank for Aatrox, because the most toplaners are tanks or bruisers.
You need lifesteal to spam your abilities, so my offensive items are only lifesteal.
In late game your team needs tanks, so my late-game items are guardian angel for amor and magicresitenc and spirit visage for MR and more lifesteal (+20%) and Randuin´s ohmen for more hp and armor, and the passiv is doubled. And don´t forget to buy the mr boots for your mr.

Make only the last hits or when your enemy doesn´t let last hit, do it with your E.
Are your hp low autoatack the minions and heal yourself.

Solo:
Jump with your Q to the enemie and then slow him with your E and deal damage with your W.
When your life go´s under 50% activate your W again and heal your life with every 3rd hit, because your W heal you 200% more when your life is under 50%.
Don´t forget to activate your R when the enemy is next to you, so you make damage by him.

Team:
Go on the carry´s with your Q and slow them with your E, then make aktivate R and W and attack them.
Then your life under 50%, aktivate your W again and heal you.