You simply have a static html page where you promote that people can advertise on your site, or do you perhaps have an announcement, or do you have paid subscriptions they can purchase?

Do you use the available vB features or a third party software solution?

Is sticking to one advertiser smart or should you spread the income over multiple?

I use phpmyads or something like that, and my shared admin takes care of everything, he analyses the pages and sections of the sites and updates once per month the views etc. I have no clue how to do that :D But it does pay the hosting bills quite well.

I really need to look into advertising. At the moment I just use subscriptions and so far my forumites have been a little slow on the uptake.

I have a dedicated which is slight over kill for the size of my forum so I need to start to make it earns its keep, instead of being a luxury item. :)

There's some powerful and free advertisement management software located at http://www.phpadsnew.com/ - Most of the larger sites I know use this. Personally, I'd probably either use Google AdSense or use Private Advertisers if I could. I think private advertisers would be a lot better considering i've heard horror stories about AdSense and related products. They make a lot of money, but I've heard of a few people being unfairly suspended.

I use Bidvertiser (http://www.bidvertiser.com), and Clicksor (http://www.clicksor.com) on my site. I use PHPAdsNew to rotate through both of them on each page reload.