Slip the first stitch of every row, front and back. Knit the last stitch as normal. This will create a nice slipped stitch edge to both sides of your blanket.
For a little added interested without any added difficulty, you can slip every 5th, 10th, or whatever stitch on right side, and knit all on the back. Depending on how many stitches you have cast on, figure a good even number to space your slipped stitches evenly across.