Let me begin by saying, if I can do this, you surely can. Keep it simple. Stick to a niche theme and blog around that theme. Think of it like a media planner at an ad agency would. I have not been a media planner, but I did study advertising in college. As with TV ratings, I assume the media planners who use new media want the maximum outreach for their dollars. So in my straightforward talk and using supply and demand principles...the more the demand for your site (measured by number of hits, the more ad dollars you will earn. In simple steps (and I'm sure you've seen this type of advice before)
1. Get a site or a hub
2. Develop somewhat interesting content
3. Monetize your site
Here are some sites that offer guidance:
Check out my site, if you want to see a simple sample. I think it's monetized. You tell me.
Now it's your turn. No excuses! If you prefer visual guidance, screenshots follow on first steps to creating your hub.