Chuck needles to keep him off guard + set up for stuff. Use throws often to make sure he doesn't get too shield happy (but they might shielddrop -> neutral a combo so watch out). The fact that he's kind of slow in the air means that it's easy to Fair chase at higher percentages. Ftilt locks are fun on Ikes, as well as maneuvering platforms to get advantages on him (lol where's your Battlefield gone, Ike? Oh wait Sheik's too fast for you). If he decides to ledgestall with Aether just charge Needles and wait.
If he uses Quick Draw and you're by the edge he's on just jump all the way out there right to him - he has two options - get hit, or release it. Depending on position it's usually wise to try and get him to release it but if that doesn't work after the first two times or so you try it just Fair.
EDIT: Oh, and spot dodge often. Spotdodging often baits stupid moves out of shield from Ike; spotdodge x however many times you want -> roll will get you past most Ikes. Remember: if you can't do it one way, do it the Drephen way.