Add content. You can’t design stuff without seeing how it behaves with content. Many types of content.
Check your site on some bigger screen (1920×1080 for example).
Don’t waste time submitting it, rather work harder on your skills. Right now you are very far from being accepted.
Ouch… Nothing personal, but as LubosVolovar said – you are far, far away from being accepted/approved for sale with this theme.
I would definitely start over…
Nothing bad actually – you just need to learn a bit more. Keep going and don’t give up!