I watched the first video only.
You're impatient.
Play around with your projectiles a bit more, and make sure you always jump when you pull out a bomb (and preferably when you use the boomerang as well.)
Link's dash attack is nice, but only if you get them at the right percent to combo into upTilt or upSmash.
Try not to stand around and wait, either. Always be fake-approaching or retreating with a plan (nair is good to get them off of you)
I feel I can't quite correct you because then I'd:
Be telling you how to play
Be telling you the way I play Link as if it were the correct way
And that's not what I'd like to do.
All in all, try to learn from your own mistakes, and try to be thinking at all times.
Also, are you on the East coast of the US or in the midwest? I can definitely show you some stuff with/my Link if you're up for it.
Just PM me.
<3
-Nox`