Instructions
Choose a location on the lake that is likely to have trout. Locations near drop-offs, food sources and structures are a good start. It is helpful to have some knowledge of these locations prior to trolling, so you can spend your time trolling for trout, and not searching for the spots.
Prepare your line. You are going to need about 200 feet of line on your reel because you will be letting the line out behind you, as you troll. You will need a three-way splitter. The splitter attaches to the main line, to another line for the weight, and to a third line for your bait. This set up ensures that the bait is trolling at the right depth of water. Adjust your weight as necessary, depending on the depth of the body of water you are trolling.
Choose your bait. You can troll for rainbow trout with live bait such as minnows, or you can use lures.
Drop your line behind your boat, and let it out about 120 feet. Travel slowly over the body of water at a speed of one to two knots. The idea behind trolling is to cover a lot of ground, so stay patient, and continue on the path of hot-spots you scouted.