Cover both sides of the wing and keep the covering moist. When finished hang the airplane by the leadouts to dry. Otherwise the top will dry faster than the bottom and may give you a warp.
It's been mentioned before to cover both sides at the same time.
I have absolutely no idea how this can be accomplished when you have silk hanging over the edges?
My efforts have paid off, I'm now silking with great results, tight as a drum and no warpage. I also use a "mist" bottle to keep the silk damp.
Pull like a mother on the tips to tighten the silk and yes, I use pins. I'm still doing it the way I learned in the late 50's.