As announced by YouTube a few days ago, it's soon going to roll out the new One Channel design to all it's user in the next few weeks.
YouTube has released a few tips for how to get ready for the transition.
Here's the original post from YouTube's blog:
Tips to get ready
1) Create a channel trailer to get people to subscribeOn your new channel, you can show a trailer that will only appear to viewers who aren’t already subscribed to your channel. This is your chance to let visitors know what your channel is all about and tell them why they should subscribe! Keep it short and to the point, and include a clear call to action inviting your audience to subscribe.
2) Create some channel artChannel art is how you can express the personality of your channel wherever it is seen, whether on a mobile phone, a tablet, a TV, or in a hovercard anywhere on the site! Here is a template and guidelines on how to start creating channel art that will look great.