I write this for Hope, because for once, I have knowledge I am proud to own, and wish to share, for those who have useless boyfriends who expand their mind all day on knowledge not including corset-lacing, or for those who don't even have a boyfriend to lace them up!
Tie the straps in a single knot. Pull this knot tight, tugging at the top and bottom webbings of lace to even them out. Now put your left finger on it to hold it tight.
If you just want to be cinched only at the waist and want room for eating and breathing and movement, then tug especially at the top- and bottom-most parts of your string column to relax these parts when adjusting your lacing tightnes. It gives you more of an hourglass figure, but doesn't push up your boobs so much.
with your left hand still on the knot, grab a right-hand strap 2/3 of the way down it and bring it to the knot, making sure you pivot your hand to grab the strap at its root as well (forming a bunny ear ready to tie up).