As to cresting- less is always more in that department. Too much banding tends to look too busy in my opinion.
Look at Bob Burton's work at Whispering Wind arrows..or Arrow Art...or some of the guys on the Sponsors Classifieds who do nice work...you'll find their stuff is much more understated than what us amateurs generally do, and it just looks BETTER.
A color wheel from an art store will really help you pick colors that compliment. Matching isn't necessary- complimenting is- like pink works well with gray. Blue is great with white- yellow and green do well together- there's lots of others and a color wheel can show you that in spades.
the prettiest arrow I've ever seen was made by Hatchet Jack Keener for the inaugural PBS arrow competition. If you Google the words PBS ARROW COMPETITION actual photos of the arrow will come up for you.
It had a coral snake skin over the shaft, with the head of the snake ON THE ARROW holding a beautiful knapped head of translucent blue gray obsidian or agate.
Jack always built snaky wood self bows...and the arrow was a 'snaky' shaft....by that I mean wavy just like a snaky bow...and it had a snake skin on it as well....get it?