If your competitor are ranking above you, they're leaving clues. Go to: pageaudit.com (it's FREE) paste in your competitor's website.

Leave "target keyword" blank.
Once it loads:

You'll see the exact phrases they're repeating on the page. That's what they're optimizing for. Those are their target keywords.
Now ask your self:
Are you using those phrases?
Are you covering that topic as deeply?
Is your page better?
If not... you know what to fix.