Ive been practicing the same thing. So here is some advice maybe you can use.
For videos go to the actual user uploaded video on Amazon, screen record it with camtasia.
So then its alll about keyword research in my opinion.
I think the best thing to do is find some products that are in the best sellers section. Or they also have most wished for.
Then take those products, and put them into google trends, normally google trends with give you related keywords.
So use those keywords, and if you are just uploading with no on site, you are robbing yourself. At least add your tags, and stuff the description with more keywords, and make a cool thumbnail.
I use a mass video uploader and all my descriptions have that built in on auto pilot.
Other good tools are seo stack for keywords, then for quick search volume put them into keywords everywhere, and sort then also keep checking in google trends for trending keywords. That is how you start to build your keyword list.
So then also there is stuff you can do to the channel. If you go around to like katy perrys channel or big PR channels you can add authority to yours just by leaving a comment in their discussion section.
Best of luck to you. Im going after local right now. Just starting to see calls trickle in.