Have you thought about bundling your tutorials into books, and selling them as a print on demand service. Take a look at http://www.lulu.com/.

Instead of selling ads for other sites, how about setting up an online store at Shopify.com and selling products that your viewers might be interested in. If you don't want to worry about order fulfillment, outsource that to Amazon.com.

Speaking of Amazon, have you looked at their affiliate network? You'd almost have to make more money than Ad Sense.