YouTube Channel Art is really important because it visually signals to viewers what your channel is all about. A common mistake made is that people design their channel art at the banner size on a computer without taking into account how it looks on different devices.
Here is a template you can use to design your channel art.
The white rectangle is how your channel art will look on a TV. The rest of the devices are only 423 pixels high, but they vary in width quite a bit. For logos and text, try to keep them in the green Safe Zone. This zone will keep that artwork from having links overlaid, so it can be easily seen and read.
So when designing your channel art, take advantage of our YouTube channel art template!