You want to earn from adsense or adwords.. If you want to earn from your blog by placing ads then you must apply for adsense, If you get adsense approval for your blog then you can start serving ads and earn money. And adwords is to promote your website, if you want to earn from adwords, then you must become affiliate of any website and start promoting it through adwords. You must invest money for adwords, if you get any sales with your affiliate url then you can make money. If you send me your blog url then i can tell you whether you can get adsense approval or not and also i can help you to get approval for adsense easily.