If you are not satisfied with the relevancy of your Google Adsense Ads and its CTR, try section targeting. By inserting a start google_ad_section_start and end google_ad_section_end html comment to mark the relevant content sections of your page.

Look into single.php

Most themes will usually consist of single.php. single.php is the file that shows your full content. Look inside, and search for

<?php the_content(); ?>

Add the section targeting codes before and after this line, making it something like this:

<!-- google_ad_section_start -->
<?php the_content(); ?>
<!-- google_ad_section_end -->

Best of Luck