I have an Android game in which I've included ads from Millennial Media and Admob. Between these two networks, my fill rate is consistently above 95%. Right now, I'm getting over 45,000 requests for ads per day, and I'm starting to see exponential growth. But, my eCpm for both Millennial and Admob is ridiculously low. Millennial's is $.12 and Admob's is $.01. I've been reading some other posts and it seems like people are getting between $1 and $4 per 1,000 views. How can increase mine?

Thank you!