You need to at least find out what is the major factor. Traffic low? CTR low or CPC low? Then only you are able to focus on the improvement
Well I guess you are on low paying niche. You need to build quality traffic for your blog and do some SEO work! Also it may be possible that you have invalid clicks on your account! Are you getting similar CPC daily?
I don't believe invalid clicks can affect payout. I think the advertisers that payed Google in that niche just have a lot of money.