I can’t offer people a whole world of knowledge yet but what I can say is that if you have been spinning your wheels and not getting anywhere, press pause on your operations for a bit (not more than a week or two at most, doing nothing will also get you nowhere) and re-educate yourself with articles like this and re-work your tactics where necessary.
Working with advertising networks isn’t your only option when it comes to selling ads. If you end up with enough traffic, advertisers may come directly to you and ask you to place their ad on your site. You can also contact advertisers yourself. The biggest difference from the above mentioned option is that there is no middle man, which means you can set your own ad rates.