I am not monetizing my blog but the eBook/ad routes seems to be the most successful way to do it. For example Dayle Rees writes blog posts on the PHP framework Laravel [1] and then compiles them into eBooks [2][3] that he sells.

[0] http://daylerees.com/

[1] http://laravel.com/

[2] https://leanpub.com/codehappy

[3] https://leanpub.com/codebright