If you can't use AdSense, I would suggest that you build up your traffic for a long enough period of time and study it.
What pages do your visitors visit the most?
What kind of internal links do they click on the most?
By paying close attention to these and other metrics, you should have a pretty decent psychographic profile of your visitors.
You should be able to get a good idea of what they would look for, what kind of problems they have, and why they end up at your website.
Armed with this information, you can come up with your own products.
These can be a small ebook, a set of diagrams, or stuff that you can scrape off the internet.
It can be many things.
Whatever the case may be, you would be better off selling your own products because they would be custom-tailored to your actual traffic.
You're in control of your sales page and the product quality.
You're also in control of the customer's experience.
On top of this, you can build a mailing list from your buyers.
Believe it or not, your mailing list is your key to success.
Why? You can sell many different products to the same list members for the lifetime of their subscription to your mailing list.
That's real money.
Instead of just settling for pennies and dimes, when people click on your AdSense ads, you make real money as your blog matures and as your newsletter grows.