Just fight a CPU ICs. (cpus never shield, but you can get used to the timing of hitting two chars lol) When I shield pressure ICs I never do the "traditional" shield pressure. Instead I use double shines, shine grabs(to dthrow), UAIR (yes uair, it hits twice and is bound to poke through one of their shields and if not you are still safe, and any other aerial as long as you are behind their shields or space it far enough away from the so you can't get grabbed.
Another amazing thing you can do is just space a fsmash. It doesn't even have to be amazing spacing because it'll push them back a ways so you can't get grabbed. Chu says he can't get around Falco's fsmash, so I don't think anyone else will lol.
As far as combos go, it's a similar process to comboing Marth except ICs will die easier off the top so you can use shine to kill them on Yoshi's, PS, Rainbow Cruise, Battlefield and less often FD(which you should probably ban btw) and FoD.
More than you asked for but w/e. =D