getting more organic traffic question

Hello... im new to seo, and i have some problems... i have created a website with up to 50mil pages, and only 200k pages indexed, anyway... my question is im getting alot of long tail keywords like:
doctor rockit the music of sound 1997 zip
losing control seany b ft sophia dj mystery remix
satelite brique rouge funky musique

now my problem is how i can improve my site more? right now im getting about 450 visits from google... i want to improve it to 1000+
i created backlinks, and wiki links so on.. i have about 50k backlinks +-... anyone can tell me what else i can do to improve my site / ranking?

50,000,000 pages? lol, that's a lot.

How old is the site?

Have you done at least a little bit of on page SEO?

Are you getting 450 uniques each day? Or are you getting 450 per month?

You should also link to inner pages/subpages. And also interlink your pages.