He said many advertisers believe achieving high scores is all about keywords, when in fact it is about the quality of the ad itself and how well it is written.
Companies should therefore focus on creating strong ads that appeal to the needs and demand of their customers.
Mr Waserman also claimed that a short list of specific keywords is better than a long list of "anything-goes" search terms.
"You don't just want a bunch of traffic, you want quality traffic that can lead to conversions," he remarked.
Inserting these keywords and phrases into the ad itself can also lead to higher conversions, he added, while ad testing is essential to keep improving scores.
Writing on the adCenter for Advertisers Blog last month, Microsoft search account manager Jeremy Lamothe recommended that internet marketing teams use no more than 20 keywords per ad group.
Clickthrough Marketing