I only watched the vs. Link one.
In the vs. Sheik and vs. Link matchup, you do realize that you can chainthrow with d-throw on the both of them, yes? I don't know if you just can't chainthrow, or don't perceive it as an "honorable" tactic, but at especially low %s, you need to chainthrow to build up enough damage so that you can start very basic combos (i.e. d-throw -> techchased down-b/side-b/stomp/f-air; u-throw -> u-air).
You also need to stop using down-b and side-b in completely unnecessary situations. In some instances, you just randomly threw out side-b's when it wouldn't even have reached. Textbook use for side-b is mostly for techchasing, and that's it. Down-b can be used in the same way, although you can often mindgame it in without too much hassle. . .provided you don't spam it.
You need to learn how to space properly. Again, randomly throwing out moves is a bad thing, because without proper planning/spacing, those moves won't accomplish anything. Ganon is good because if you space properly, people can't get inside your range to hit/grab you. If you use f-air/b-air/f-tilt/jab/u-air properly, most characters shouldn't be able to land the kind of hits that I saw you being nailed with.
You can also afford to be a little more aggressive. You did a shffl'd aerial, and then just stood there waiting for the Link to respond. You can pressure him if you have the spare time with aerials, dash-dance, do ANYTHING to try and get the Link in a disadvantageous position. Just standing there really doesn't accomplish anything.
Edgeguard with u-air, too.
