Keep it simple. Make sure your banner includes your channel name, and possibly a tagline that outlines what you do. Clean lines and colours tend to look decent, and anything that personalizes the banner an idea of what the channel is about is awesome! As far as logo goes, that is very much up to you. I know people who use their name, or a mascot, or a picture/artwork of themselves for their logo. It depends again on what your channel is all about and what image you want to show. Looking at what you have currently, I think it doesnt look too bad! Your logo is good, I would make the N bigger though. As far as the channel art, I don't really understand the symbols above your name, personally i would put the name on the top and make it bigger, and then make the symbols a little smaller. Hope this helps!