Select Secondary Keyphrases
When selecting a primary keyphrase for a webpage, you may also want to select one to four secondary keyphrases. Using multiple keyphrases can help make your page appear more comprehensive and less spammy to search engines. For instance, the relevancy algorithm Google may cast a dim view of a page that mentions blood donation 16 times but makes no mention of "red cross," "blood donor," or "blood types." Thus, use a few secondary keyphrases that are related to your primary keyphrase.
While the most popular keyphrase for your topic might be "drunk driving," you'll want the search engines to also find related words within your copy to ensure that you have covered all the ways in which people might search for your topic. In addition to "drunk driving," also include "driving drunk," "driving under the influence," "DUI," "driving while intoxicated," "DWI," and so on.
As a bonus, simply adding a word or two in front of your primary keyphrase can make your PageRank well for multiple search terms. For example, the keyphrase "autistic children" may easily be turned into "teaching autistic children," "educating autistic children," or "special education for autistic children."
When adding words, make sure that each keyphrase can stand alone. "Teaching and educating autistic children" will only rank well for two keyphrases, while "teaching autistic children and educating autistic children" will rank for three.