In selling advertising on your site, there's two basic options. You can sign up with a program that gets the advertisers for you, or you can find them yourself.
Obviously, the advantage to a program is that you have to do a lot less work. However, whoever is running the program is the one who has final control over who can advertise on your site. Not only that, but they take a big cut of the profits that way. If an advertiser paid $0.50 when someone clicks on their ad, you might end up with $0.05 of that.
You also have to worry about whoever runs the program deciding randomly that someone's been clicking on ads on your site just to drive your revenue up. When they think that happened (and they often do, even if it isn't the case), they can just cut you off with little explanation.
My advice? Eliminate the middle-man. Find the advertisers yourself. You'll have to do a bit more work, but the profits will be much higher.
There's a couple of ways for finding potential advertisers. Off-line, you can directly contact potential advertisers in the community. You can even offer to design the banner ad for them as well, if that's the type of advertising you will be selling.
Remember, you will likely have a low ratio of people wanting to advertise versus the people you contacted. Don't get discouraged. It takes time at first.
Online, you can start hanging out in forums potential advertisers would hang out in as well. Be sure to actually contribute valid content to the forums (not just fluff), and then after you have more of a feel for who knows what they're talking about, start asking away.
Use a combination of the two methods, and come up with new ones as well. No matter how you do it, getting your own advertisers can pay off in the long run.
Tim is the owner and senior web designer at T&S Web Design. His company has developed and maintained website for dozens of small businesses and organizations. Tim also maintains a blog with free website advice for small business owners, GetASiteOnline.com.