The Linnaeus cowl is knit with ease in mind, so only minimal blocking is required. The picot edge does have a tendency to not want to lie flat, so I recommend blocking with Knitters Pride Knit Blockers and blocking wires (mine came from Knit Picks).
Step One: Soak your cowl using lukewarm water. You can use a light wool wash such as Eucalan, which I prefer because you don't have to rinse it out. Soak for 15 to 20 minutes.
Step Two: Take your cowl out of the water and lay on a çlean, dry towel. Then, fold the towel over the cowl and press hard it to make sure the cowl isn't sopping wet.
Step Three: Lay your cowl out on your blocking mats. Plenty of blocking mats are available. Mine are in fact four squares of exercise flooring purchased from Lowe's.
Step Four: Put two blocking wires on either end of your cowl as shown above. Using the larger size of the Knit Blockers, put two on one end in front of the wire. This will keep the wire straight. Pull on the unpinned edge until the cowl is the desired width. Do the same for the other side.
Step Five: Block out your picots. I've done this just by putting Knit Blockers across the edge with the picots to allow them to dry flat. If you'd like to pin out each one individually, you can match up each side to save pins. I prefer to think of this picot edge as a fringe and allow it to block with some flexibility.
Step Six: Place more Knit Blockers around edges as you'd like. If you would like your top edge (the cast on edge) to be very straight, you can use another blocking wire to guide this line as you did on the sides.
And there you have it! A blocked cowl. Let the cowl dry in this position (probably overnight depending on the humidity).
You can buy Linnaeus on Ravelry.