For something specific as they've already told you to look into tutorials, I'd same focus on a color scheme that works well. Related colors that blend well. Red clashes too much with green and the other is just plain random. Also, the sizing is huge, too big for NGU anyways. Try to keep it under 500x125.
Tutorials lack originality. Learn Photoshop yourself. It may take longer, but it's definitely more rewarding. Also, you can say that you're truly unique with your work. =D
I like the first one, it isn't bad, especially since you've just started. The second one is a bit lacking in style and point.