This topic is not as important as it is commonly believed to be.

Put phrases that relate to your content in the keywords line, separated by commas. Do not bother including very common phrases, such as “expert” or “rock and roll”. The keywords line should always be tailored for the particular page. If it is the same for every page on your site, you are better off not using the keywords line at all.

Do not overload the keywords line. As a rule of thumb, if you are putting things in the keywords that are not in the rest of your page, you are probably putting in too many.