From your first video, you should learn some more combos. After



, you can combo into




> GS


. After



you can do GS(



)


. Also, CH WR

> NSS



>




is a fine combo, but when you're close to a wall, you can do GS(



)


instead of




and get a wall splat for more damage and the still end with




. For a quick run through on combo staples to learn and incorporate into your game, check out this video...
One last thing, it's usually not a good idea to finish



because the last hit has a really slow recovery. That combo is only guaranteed on CH, so other than that, don't use it.
EDIT: After watching your second video, you should mix up your grabs more.



is good for ROs and wall splat, but



does more damage and leaves the opponent at your feet for better pressure afterward.
I can't really say much else on the defensive end since you're playing against a computer, so that's all for now. Work on the combos and such.