User blog comment:CapnJedders/AP champion cs frustrations/@comment-6061249-20131029202210

Lasthitting under turret with AP champions isn't honestly that hard. You just need to have a special tactic of reducing minion's health before it comes to the turret.

The only problem is, you have to properly choose the target while counting in before done damage, turret damage, and... minion damage. Minion, goddamn, damage, which steals even more creeps than turrets.

Simply, if you can't lasthit a caster minion after it gets hit once by turret, do a one hit before it approaches turret's aggro, and after that its remaining health should be enough low. It's quite hard to manage at first, but after some practice you'll be able to lasthit 3/4 of creeps straight under turret. You can also reduce minions' health with spells, and perform lasthits with turret + your AAs.