I see you post from graphicriver.
1) An idea would be to extend your portfolio with other flyers, for instance club flyers, kids party flyers and especially corporate events flyers would go best.
2) Since you are proficient with Photoshop, you could try creating web display mockups (these are bought especially by themeforest/codecanyon authors, these always have a high selling rate).
3) Another idea for you would be to associate yourself with a themeforest/codecanyon author for the design part.
4) Also, pay attention to tags you put to your items when you upload/edit your items. Tags are very important for the search functionality (how people find your item).
5) Or post a link to your item on graphicriver social pages (facebook, pinterest, behance, etc)
6) Also, try to find review websites and submit links to your items for review/they link back to your graphicriver item)
7) And of course – extend your portfolio.
I am not an author with so many sales, but this is what I would do.
I planned to do these for myself, but I can’t find the time to do that LOL