It certainly takes a fair bit of dodging. You need to posture forward within the minion wave so that you can trade on them when they try to last hit a minion. Whenever they get within range, you W>Q forward and smack them a few times. Then you can walk away, or E if you must so that you can get away from a charm or something similar. But definitely posture forward and try to push them off the minion wave. Usually they'll either spend all their mana trying to last hit or they'll spend a lot of time farming under tower--both bad for them.
If you aren't already, try starting a corrupting potion. It really helps that play pattern. Just make sure you're abusing his passive so that you can close on them from angles others wouldn't and escape through the wave so they can't chase you directly.
Lastly, punish them for missing skillshots. If they try to use their stun on you, E forward to dodge it and smack them a few times before escaping with a Q to a minion if you can't just back out.