I know this is kind of old, and I'm not exactly an expert on fighting Ganon, but I thought I'd try to help anyway.
You seem to hang out on the platforms too much when you're opponents below. Many characters can do some nasty things while you're up there. If you play against a Marth, avoid that situation at ALL costs.
Another thing you want to do is use your second jump less frequently. If you get knocked off the stage after you use it, it makes it a lot harder to recover.
Also, I've always preferred using shine>dair while I'm already in the air, since Falco's second jump is MUCH faster than his first jump. Of course, when you shine on the ground, you want it to be a waveshine. A good switch up from the shine would be up tilt, which is an excellent move.
A good thing to get down is shortening your side b's. This can be done by hitting b a second time after you use your side b. However, it takes some pretty precise timing. This is good when you're closer to the stage, obviously. What makes it so good is that most of the time, your opponent will expect you to do a full side b. By doing a shortened one, you find you'll make it back to the stage more often.
You should also mix things up more. If you get too predictable, you'll find yourself not landing too many hits. Everyone has a pattern, but the more you mix yours up, the better.
One last piece of advice. I highly recommend you read Hugs' blog. I know it helped me quite a lot, and I'm sure it would help you too.
http://www.genesisdbr.com/blog/?p=46
Btw, considering this was after half a year after you started playing smash seriously, I have this to say: you're MUCH better than I was half a year in! Just work at it, and I think you could be a pretty good player. =)