Channel art is most effective when it is representative of the channel’s content. For example, if your channel is about the hottest new shoes, your channel art should include images of shoes.
The YouTube channel art section is in the large gray box at the top of the My Channel page when viewing on a computer. (It will look differently on other devices like mobile phones and TVs, but a computer is the only device you can use to change your channel art, so start there.)
By default, it has a few items in it, and you’re going to change pretty much all those items. Before getting into the steps of creating your channel art, though, you should keep some important guidelines in mind. YouTube is available on a lot of different devices.
Your audience may be watching on a TV, a computer, or a mobile device. Given that fact, YouTube has gone to a lot of effort to create a system that allows your channel to look good across all kinds of delivery platforms. It has come up with some guidelines for artwork that you would be wise to follow.
If you pay attention to the size of the graphics needed, you should have no trouble with your channel looking good, no matter how your audience is looking at it.