Never start your pricing too high. It is better to error on the low side and get advertisers hooked, because then they will be willing to pay higher prices for your inventory when the pricing increases.
Make sure your placement is worth buying, the popular sellers in the marketplace tend to be sites with the most premium inventory.
Spend some time tagging your site and giving proper demographic information.
In your site description provide ideas of advertisers that you think might convert well. You know your audience best.
AdBrite is more successful if you sell a FEW premium placements as opposed to just MANY backfill placements.
Hard code all placements because of the concreteness of "your ad here". Putting AdBrite in rotation doesn't perform as well.
Allow a ramping period. AdBrite is a tool to help sell your own inventory, and think of it as a virtual salesperson for you. Any salesperson needs some time to gain traction. Just like an auction, the beginning price is never the final price.
Entice advertisers with specials. You have full control to set pricing so make occasional specials to entice advertisers.
Enable AdBrite's auto pricing which will raise automatically as inventory sells, and lower itself as vacant inventory sits unsold.