here is the deal with facebook, understand they are in business to make money. Any new ad will get more run with them so they can gauge how much they can and will make from it. Once you understand that you can work around it. As a test find an ad that you are getting few impressions with, click "create a similar ad" and don't change a thing at all with it. You will see your "new" ad getting more impressions even though they are the exact same. Another thing I tested was doing what I just described and lowering the bid 1 cent, sure enough the "new" ad with a lower bid got more impressions over the next 72 hrs even though it was the exact same.
Another tip is to move the bids up a fraction in the afternoons, as more people hit their daily budgets it will get your ads into the rotation more.
Constantly create "new" ads, even if the wording is the same, change the picture, play around with the ages a bit, do stupid little things and you will notice yourself getting more bang for your buck.
Let me know how all of that works out for you.