Dutch, if you're still tying, here's the best how-to article I've seen on harness making:
http://www.walleyesinc.com/walleyeinc3/howtotie.html
Otherwise, assuming you have a bowmount electric with sonar and GPS....drop your bouncer/harness down to bottom as the boat is moving, then let out a bit more to re-contact bottom, more if needed, and hold. You want to run your weight just off bottom, rather than dragging it, but close enough so that you can just swing your rod back a few feet to re-establish contact with the bottom. Adjust as needed for changes in depth and speed (more depth/higher speed = more line out). In general, the less line you have out the better. Straight down is great, for water over 12 feet or so,, and never run your line at an angle greater than 45 degrees behind you. Reel up and re-drop if you need to--only takes a few seconds.
Troll your harness fast enough to turn the blade and provide a little lift, and slow enough to make it an easy meal. Walleyes just love to slowly suck those things in--seldom will they slam it, so usually you'll have to nurse the bite a bit until they've taken it firmly. Hold steady, and let the fish load the rod, then sweep-set. Move along at 0.7 to 1.5 mph GPS--average 1 mph works great.
Rule of thumb is to use 1 oz. of weight for every 10 feet of depth, but I use 2 oz. for just about all situations. As long as you're sure you're getting down, and not dredging bottom, you're fine.
You'll get a feel for it in no time. Bluegills peck at a harness like a machine gun, bass and catfish usually take it hard and aggressive, and walleyes deliver a sudden heaviness and (when active) a slow pulsing feel. When the rod loads, the battle's on.