Slip Stitch patterns are easy. Only one color is used at a time, but many colors may be used in the piece. In the picture below, two colors are used and the contrast color not only slips the stitches, but has floats that show on the right side. Because the slipped stitches pop out, and stitches tend to be uneven, there are a couple of things that can be done to give professional results.
1. Work to have even tension. If the slip stitches look too large, try knitting at the tips of the needles and make sure floats are not too large. If the slip stitches look too small, work further away from the tips of the needles and make sure the floats are long enough.
2. Block the knitted pieces. Yes, get it wet and lay it out on a blocking board or on towels. Even steam blocking will help some. Blocking will flatten the work out and give it that professional look with stable stitches.
Enjoy slip stitches, they add a lot of effect for little work. Brocade vest below is available at http://www.ravelry.com/designers/margie-mitchell