Yeah speed is another thing I forgot to mention that is a big part. If your pulling harnesses you usually want to go slow, probably not much over 1.5 mph and focus around 1 mph usually. Depending on what cranks your pulling you may speed up to even 2.5 mph to get the action you need. Some days they like it fast and some days they like it slow to just like any other type of fishing.
If you get into it a little more your best inverstment will be definitely be the trollers bible from precision trolling. It gives you the dive curve for almost any lure imaginable as well as curves when using weights. Gives you more confidence in knowing where your baits are.