sheild and dodge a lot. Ikes attacks are powerful but once u take it witha sheild, you have a nice opening for a counter.
I wouldnt try to do any direct frontal attacks unless your sure he cant meet your attacks with one of his.
avoid using the homing attack because he has a lot fo moves that counter it, and if he meets it with a smash your gone. dont fight from above him, definatyle try to get him above you, and if he is in the air you can probobly chase and if you do it fast enuff he wont have any reaction time.
the spin dash attack is a good option, as always for the sheer speed of it, if he uses his forward b it will only ting the down b spindash anyway, and you have the option to jump over him and come in behind him after he stops.
basicly, your goign to need him at around 200 damage before you can kill so just get a lot of spam in, Fair's jabs, tilts, hyphen-smash
when he is at 200, you best options for killing is going to be Fsmash, Dmsash and Bair
I dont think the Uair would work well on ike because he has counter, Down B, and can out priority it with his Dair
you could try the running attack, turn around Fsmash.. but to avoid a bair, i would rooll back in front of hima nd then Fsmash as he lands.
also if u run near him, sheild/dodge an attack or two, then catch him with Dsmash or Fsmash during his post attack delay.
Bair can be used at any time provided that it is unexpected. it should be easy to catch him off gaurd with it...