Use the minion wave to block Aatrox from landing his W and going for the all-in. Always ensure that there is at least 1 minion between you and him at all times.
Both his Q and E have rather long cooldowns in the early game. If he uses them, try to abuse the cooldowns and look to trade with him while they’re down.
Aatrox benefits from bursty trades around his Q. Try and keep your distance at all times and be prepared to sacrifice a little bit of CS so he doesn’t burst you down.
In team fights, as soon as Aatrox runs in, try to CC him and burst him down first. He is pretty vulnerable to CC and if you can kill him before he gets his combo off, the enemy will lose out on a lot of damage.
Try to look for fights when Aatrox doesn’t have his Ultimate R or Flash. He will have a much harder time at impacting fights when either of these are on cooldown.
Aatrox likes to split push after the laning phase has ended. When he shows in a side lane alone, you could try and start a team fight with his teammates. Have wards on that side of the map though just in case he makes his way to join the fight.
Aatrox is strong from levels 2-6. Make sure you keep your distance to make it harder for him to land his Q and poke you down.
Aatrox spikes when he gets his first item (as well as both component items). Respect his all in potential when he’s completed the recipe as his damage output will heavily increase.
Aatrox is really strong no matter what if you cannot dodge all instances of his Q. Practice makes perfect, but do try and dodge them whenever you’re able to.