Another question I got from the Abbot test knitters was about carrying the unused color. The unused yarn is carried over 3 stitches and up 2 rows. Not a particularly long length, but one that needs some care to avoid holes and keep the tension even. You definitely don't want to cut and sew the ends for every color change!
When switching colors, I brought the new color up from under the old one, creating a simple wrap. Then worked the first three stitches (k1, slip, k1). Then took both strands and gently tugged them to the right, evening the tension. It's important not to pull too hard to avoid puckers. And not so loosely that you have yarn loops on the back.
When worked evenly, the back of the shawl looks like this (hard to read, but it says "yarn carried on back").