Your two biggest earners will probably be under the first post ads and ads on the top right. Both of those are pretty good sellers on BSA. Also, a footer ad like you have generally doesn't make much.
It looks like you currently using adsense. From my experience buysellads is a pretty good option and you can use adsense backfill so when your ad is not sold, adsense will display. Other ways of making money is selling premium membership.
Hmm.. if you want something in addition to the advertisement route, maybe a program where members can sell their photographs on your site but for a fee, so x percent of commission goes to yourself? Or selling your photos on the forum? I think another interesting service would be offering consultations to people who want help with improving their photography or are having an issue with their camera.
You seem to have some sponsorships going already so you could try finding more companies.
