Try partnering with someone/a business who has an existing userbase that resembles somewhat yours - this usually means that there is a potential conflict of interest, but it's worth trying.
Partner with them to get them to send out information and links via an email newsletter (they MUST have CAN-SPAM valid user emails, NOT 'harvested' emails). You could do the same in return from them - it would be a win-win situation.
From a different angle, ensure that your website is as optimized as possible. This means:
- page load time
- search engine friendly
- great content
- easy to navigate
- other criteria as well, most likely!
If you're making money with your blog, it likely means that there is some sort of user conversion workflow - the path which you want the user to follow that makes you money. It could be a direct purchase, a valid email sign-up, completing a form - the possibilities are endless. What is important is that this path is optimized, and for that you might try something like Google Web Optimizer (GWO).
Coupled with Google Analytics (GA), GWO can really improve your blog's income - but it takes quite a bit of work and fiddling with content and paths.
I hope this helps - even if it is a BIT techy. Good luck!
James A