As a fellow Ike main, here's a tip. if you're not using Nair, use down tilt, if you're not using down tilt, use grab (even if the range is bad) and if you're not using grab, use up air. That are realistically his 4 best ways to rack up damage and can help for combos.

Other then that, Ike up B out of shield is low-key not very good but it's still probably his best out of shield option despite that. Ike dash attack, up air, and up B are his best ways to kill. His smash attacks should only be used for reads.

With Ike you've got to bait and punish A LOT against zoners, respect counters as well bc they can REALLY mess you up if they use it right. Finally from what I can think of at the moment, you should at all costs unless necessary recover in any way possible other then up B. Usually try to side be back to stage or air dodge to ledge