1. Create a new ad campaign
2. Define your demographics. Till you know them, you can just leave the Age and Gender as Default.
3. Choose: United States, Australia and/or Canada as Location.
4. Here is the secret that no one reveals: DO WHATEVER YOU WANT!!! Yeap! That's right. You can do CPC and choose FB to optimize it for you or you can do the same and define a maximum CPC by your own. You can do CPM, or just go for "Likes". You can use a nice, clean image that you bought from a commercial site, or a crappy image you got from Google or you even created on your own in Windows Paint!!!
5. Let this go on for a couple of days.
You can even choose to Promote a Post (a bit more expensive, but if you do this for an affiliate post or for a post selling a product, this is a certain WIN-WIN situation).
To rephrase the huge philosopher of science Paul Feyerabend nowadays in FB ads "Anything goes".
WHat you can do to increase your profit? Create a bunch of diffferent campaigns to find the one that will achieve CPC between $0.00 and $0.01. This should be your goal. Anything else is a mere failure.