Cool new one MK, I really like the layout of the pictures, how the ones on either side kind of "match up" with the scene they're from. Although I may have personally placed the caption a bit more to the right, the idea is still really nice. (Willow/Tara, yay! :yay: )
As for advice, it would depend on what program you're using. If you want any general advice on banners, or have specific questions I'd be happy to help out as much as I can (just a pm away). Other than that, tutorials are great for learning new things, and posting specific questions on your art thread (preferably with more stuff *wink wink, nudge nudge*😉) is usually a pretty good way to get some help.
So keep it up, and don't be afraid to try new things with your banners!
edit: if you are using Paint Shop Pro/Photoshop, remember there's a thread for tips and tricks on the main art area too