What kind of blog do you have? If it is a review site, where you research products and post reviews on them, Amazon is good. Chitika as well. Adsense is always a good idea, but don't expect easy money from adsense or chitika. Look for direct sales programs, like amazon, game.com, play.com etc. if you review products
Its depends on you blog, but the best is probably neverblueads followed by cpastorm (both are NET15 via PayPal), freebie offers are good to start off with and typically pay $2.50 to $4 / free sign up
you def have to match your niche. if you blog about making money online, make money aff programs will do well. If you blog about football, make money aff programs probably will not do well.
First things first, increase traffic to your blog! Then utilize an affiliate program that works in conjunction with the theme of your blog. For traffic, I'd recommend using hit exchanges like easyhits4u.