To get more pertinent ads, you can tell AdSense to ignore some sections of your page, and to use specific sections to find relevant keywords for ad targeting. This will bring you more relevant ads, increasing your income.

Typically you’d like to target the post content, or part of it, and to ignore the navigation bar and the comments section, since they can contain unrelated keywords. Be sure to include a significant amount of text, to avoid bad targeting.

To ignore a section use

<!-- google_ad_section_start(weight=ignore) -->
section_to_ignore
<!-- google_ad_section_end -->

To target a section use

<!-- google_ad_section_start-->
section_to_target
<!-- google_ad_section_end -->