Mods:

• Did not crochet edge on zipper edges. I folded the steek stitch under and machine sewed the zipper.
• Knit moss stitch rather than rib on cuffs and bottom band. Knit bands only 3 cm wide.
• Added short rows to back neck. I started the first short row 7 stitches from the steek, and knit 3 stitches between each set of short rows, except for the last set, where I only knit 2 stitches between sets. I highly recommend adding short rows! It added about 2 inches to the back neck, and makes the jacket fit better and be more comfortable to wear. I used the German short row method, described here and here.
• I used the red as my contrast colour (inside neck).

I think this is a very good tutorial for steeking. Another great hint for steeking is to knit the 2 (or 3) colours together on the purl (steek) stitch so that everything gets stitched in nicely on the machine (no long contrast-colour floats just hanging there). Also, this makes it easier to see your steek stitch when you are sewing, as it will not be obscured by the contrast-colour floats.