You have to keep an eye on the performance report. To make it simple and easy Google has given the option of creating custom channels in AdSense so that you can track individual ads performance.
What is a custom channel?
Custom channels in AdSense helps you in tracking the performance of specific ad units. You can create your custom channels and group the ads in the way you like. For example you can group the ads on the basis of Ad colors and sizes, location of ads, page topis, etc.Creating Custom Channels in AdSense
You can create custom channels in two ways. The first one is when you create or edit an ad unit you can add a custom channel for that ad unit. In the second method you can create custom channel and add the ad units later. I have explained both the methods below.• First Method-
i) Visit Google AdSense and sign in to your account.
ii) Select an existing ad unit or create a new ad unit to add a channel. Create a custom channel by clicking the New custom channel button in the Custom channels section.
iii) Give a name to your custom channel so that you can easily identify what type of ad units you are tracking with this channel.
iv) You can add additional ad units in this channel by clicking the Add button.
v) Now save the channel and you can continue to customize the new ad units.
• Second Method-
i) Visit Google AdSense and sign in to your account.
ii) Now go to My ads tab and choose Custom channels option.
iii) Create new custom channel by clicking New custom channel and give your channel a name so that you can easily know which ad unit you are tracking with this channel.
iv) Add the ad units to track with this channel by clicking the Add button. You can also do it later.
v) Now save your channel and it's done.
You can view the channel's report from the Performance reports tab.