Aatrox is amazing early game, and if played properly amazing mid game. His infinite abilities and good right click damage combined with all healing he has he is a force to be rekoned with. Try to win lanes with trades using conqueror. Use your dash combined with your blade to get the skill easier to land. Try to not die, cause aatrox is really bad if he falls behind. Late game he is not very usefull, he can be kited a lot. Saving flash for this is key, since one flash combo can be game changer if you catch their ADC or MID lane carry. Use your ultimate at the beggining of the fight since it lasts for quite a while.