Use Overture's Inventory tool as a starting point for your pay per click keyword research. This will help you to generate a rough list of keywords you could use for your niche. You can then segment this list by considering the keyword groups within it. For instance, are there 5 or 10 keyphrases that share the same two word base? Put them together on the same list.

Always test different pay per click advertisements against each other. For each campaign, create multiple advertisement groups with the same keywords. Slowly thin these down to the groups that maintain the highest conversion rates. Pit the high converters against new groups until you have determined your best ad for both click-thru rates and conversion rates.

Pay careful attention to your pay per click campaigns. In many cases the network through which you advertised with freeze your ads for different reasons. Google Adwords, for instance, will stop ads that are underperforming, which means they either are drawing a small amount of impressions or have a low click-thru rate. To make sure all of your ads stay active, watch them carefully and make changes when required.

Constantly tweak the wording of your pay per click campaigns to determine the best arrangement of words. For instance, try switching the first line with the third or the second line with the third. Try all different permutations that make sense and then take note of your click-thru rates. Additionally, take note of whether your conversion rates remain the same or change.

Always use a call to action in your pay per click campaigns. Some calls to action include "click here", "start now", "join now", "learn more" and "don't miss out". These calls to action will provoke those who read the advertisement to click, rather than wandering off to the next advertisement to see if it might offer something better.

Take advantage of contextual advertising programs that allow you to select where your advertisements will be published. Google Adwords now offers this. If you notice that your click thru rate is unusually high with the Content Network, even though the conversion rates are disturbingly low, you should consider weeding out some of the potential problem sites.

In addition to all of the major networks, you may also want to setup pay per click advertising on smaller, less expensive networks. While the traffic probably wont be as targeted and subsequently wont convert as well you will gain another avenue of promotion and more than likely pay less than you normally do per click.

By all means, be persistent and keep testing and tracking to find the best ads for your PPC campaign.