Google adsense is very promising for now, because the high payment makes the publisher hard to accept [approved]. Well do not be too sad because it is often processed by mbah google, here I suggest to choose the best google adsense alternative that I ever follow.
Adsense Alternatives Apart from Google:
1. AdHitz - www.adhitz.com/
2. Bidvertsiser - www.bidvertiser.com/
3. Chitika - chitika.com/
4. Adsoid - adsoid.com/
5. Revenuehits - www.revenuehits.com/
This is the best 5 as an alternative to adsense I suggest, if you want to select another lot. You can also choose pop-up ads like pop-cash, pop-ads net, ouo.io and many more.
The point is if you have a blog that has not been accepted by google adsense, keep Up-to-date [update] your article, multiply useful articles, definitely one day will be accepted by google.
Because however strict / difficult in approve by google certainly one day later you can answer.