I'm learning last hitting minions and get the advices to kill minions under my turret.

But I'm with problems when my minion wave encounters the enemy minion wave.

I think kind of "chaotic" to detect when last hit the minion because sometimes a lot of friendly minions attacks only one enemy minion, and the hp lowers very fast... Sometimes I think myself challenging my minions about who will last hit the enemy!

How do I to beat my minions when battling against enemy minion waves?