There's plenty of commission pay per click opportunities - but then, most people blogging are using PPC ads already. So if I am telling you what you know already, my apologies - but there might be something here to help.
Run a Google search for sites with similar content to your blog. Go to those sites, look for ads that you could use, chase those ads back to the originator's site and look for the affiliate link that will allow you to sign up for the affiliate program (usually a tiny "affiliates" link in the bottom line).
Don't be embarrassed to do this - remember that the advertiser will get commission for signing up another affiliate, so leave his links in the chain.
Quite often, this leads to a source of more useful PPC links, so you find enough to festoon your site with ads.
Given that you are getting traffic already, this will allow you to see what type of ad works best, and you can select other ads to complement them.
It's DIY Adsense, but I would not recommend the only alternative I know of - I don't like a lot of what they advertise. If you start searching as I recommended, you will probably see what I mean.