Wrong keyword phrase

Ads do not use highest density phrase

[kelbra]

I am a writer and new to SEO. An article I wrote with a high paying keyword phrase was not used. A word was picked that was 5%, and the ads placed by my article have nothing to do with my subject. My keywords were caffeine addiction and diet is the keyword that was picked as in diet coke. Any advice for me?

[longen]

If the SE's didn't pick up your key phrase it may be that your article was "keyword based" rather than having been written in natural language for people to read (rather than SE Bots).
In any case if you create further pages on related topics and link to them with suitable anchor text there might be an improvement. You can get ideas for other articles using Google's Keyword Tool.

[Robert Charlton]

This sounds like it's a question about Adsense ads appearing on the page... not a question about SEO. I assume that the goal here was to get Adsense ads targeting certain (high priced) phrases to appear on the page.

From what I've observed in Adsense targeting... and I don't do Adsense myself... co-occurring words are used much more than they would be in competitive SEO.

You can get ideas for other articles using Google's Keyword Tool.

I'd be careful about dropping in too many synonyms based are the Google Keyword Tool, but used with restraint, this might not be a bad approach.

What you need to do is to describe the subject you're targeting, in natural language as longen suggests, not just drop in some keywords. Natural language will give you the natural co-occurring vocabulary that you're apparently missing.

An example of co-occurring vocabulary... if you wrote an article about the White House, it would be natural to expect words and phrases like "president", "united states," and "washington dc" to appear in that article. You might have an article containing the phrase "White House" that doesn't contain these words, but it would be strange to have an article about the White House that didn't contain them.

In your case, the keywords you're using are apparently natural co-occurring vocabulary for articles in the subject area of the phrases being matched up with your article.