Google AdSense team shared the another video about placement targeting: tips:
- Make sections of your site available to be targeted directly by AdWords advertisers with ad placements. These easy-to-implement changes will make your website and channels more marketable to advertisers, which in turn will increase your overall earning potential.
- Market your website with DoubleClick Ad Planner so advertisers can easily locate sites like yours that match their target audiences.
- Optimize your ad units by enabling both text and image ads, using top-performing ad unit sizes, and placing ads "above the fold" o that they're immediately visible to your users.
More Info: Help Center