Same as @charlie4282 . Spend more time on http://tutsplus.com/, look at some new flyers existing on GraphicRiver (don’t copy them!!! Just analize them) and some from another design websites (behance, dribbble, pinterest, even tumblr - there are some design blogs).
Don’t give up! You just have to learn. We all had to learn before we selling, even when we got rejected 
:)) it was a reason to learn more…
Good luck!