trolling questions

hey guys help me out a bit if you can. wanting to try some trolling at a lake where im having trouble finding fish. problem is i dont know how to do it. my plan is to tie 1 or 2 jigs on each rod and cast them out behide the boat and maybe let out alittle more line on top of that. i was thinking about 50ft of line. then i was gonna prop the rods up at about the 11:00 position and take off with the trolling motor on the lowest speed. i assume you watch the rod tips for the bite. Am i close? what can you guys add or correct me on to help me get started. what methode do you use to make sure you let out the same amount of line each time? is there any general formulas you can follow to acheive certain depths? amount of line + jig size + speed= depth? any help would be great.

I'm not the best fisherman,but this is what I do.
I will troll as slow as possible,using 4 poles with 2-3 jigs on each ,with different colors,so I can possibly find the color the fish want that day. I watch my sonar & the surface of the water for bait fish. I try to circle over the schools of fish with jigs set just under them. I may have one pole set to run just off the bottom,just in case, of some that may be deeper.
If I find crappie I may fish a few more poles. I'm sure I left something out,I hope this helps.

How about this: http://www.crappie.com/articles/spider.htm

Some variation of spider rigging or slow vertical trolling is the easiest way to know how deep and where your baits are running, not to mention offering a lot of different baits/lures. That article is great at explaining it.