Hi Rocky!
-First of all, you need to customise your layout! To do that, click on the toggle next to the sub button. Then enable Customise layout. Edit your main page to make it more professional!
-Your channel banner is a bit too simple. You need to add more stuffs onto it. Pictures of the Bros? Human? Sky? Rock? Top? Add more stuffs!
-Your thumbnails are good! Maybe add "RockyTopBros" or "RTB" at the corner would be nice!
Keep up the good work!