Here is a channel branding template I created to brand my YouTube channel. I am just starting out and I found that branding your channel takes time. Precious time. This is why I took a shortcut and designed this PSD file in Photoshop CC 2017 to ease the pain so I can focus on the branding part.
For this to work you need at least Photoshop CC 2015. The file uses Image assets feature and automatically generates the files for you at the right resolution. These files include: profile image, channel art image, and thumbnails.
I hope this will help you. You can download the channel branding template from the link below.