Facebook advertising question

I am trying to advertise on facebook but need a little help. My first question is this. When I add more than one keyword in the precise interest area it doesn’t narrow my field of people to advertise too. Rather to makes it larger. For example, if I want to advertise to people who enjoy blogging about cameras, I put the keywords blogging and cameras but it will advertise to people who’s interests are either blogging or cameras but I want people who are interested in blogging and cameras to narrow it down. Is it possible to do this?

Second, I read that CPM is better if you want to get people to like your facebook page since if you have a good click through rate you can get the Cost per click down to pretty cheap. What other methods can I use to get my cost per click down. I only have a budget of $20 per day so I am trying to get the most bang for my buck. Is it better to do CPM and narrow your audeince down to a few thousand.

I tried CPM out with an audience of about 4 million and a max budget of $10 and I reached my budget within like 10 minutes. I received about 6 likes and 12 clicks on facebook in that time but with a cost per click of about $0.8 that is just way too high. Any advice on getting better results for less money?

Thanks for any help