It could be anything. 300 successful article submission is nothing. Link to inner pages and make sure you are using proper anchor texts and making sure your tags are formatted properly. Also, If you are in a niche that is saturated, don't expect to move up anytime soon.
300 articles was the best i could do with AMR! they list 4500 directories. by the time i register, confirm, submit, get approved, only 300 left!
I fixed the HTML in article and resubmit, fixed a few category mis-matches.. and nothing i do would increase my approved counts!
how do i get more approved?