Once you have decent traffic set-up advertising with the Google Adsense network. It's free and all they do is give you a piece of code to put on your blog.
When someone clicks they pay you over half of the net amount the advertiser paid
to have their ad show up.
This takes time but countless people have started blogs that now pay them over six figures
on auto-pilot, with time and much effort of course.
Finding legit ways to make money online isn't hard, once you find something you can get excited about just grab it and run with it till you get to the income level you want.