If my team even kind of knows what they are doing I can usually CC him to death at the turret and if I'm alone then I can get him low enough and let him pop his ult and time my ult to not take any damage. If I play a ranged AD carry then I just don't engage him unless I have tons of damage, crit, lifesteal, and a wit's end. The lifesteal and wit's end help to limit the damage he reflects back to you if he has a thornmail on. This usually lets me tear him up end game as twitch if built properly...but I only do that if he's being a really huge pain and causing our whole team to die.

Basically, counter him with items, range, cc, and your turrets. Use the tools given to you and you will usually beat him.