Lake trout, also known as mackinaw are not really trout, they are actually a member of the char family. 

These fish need cold well oxygenated water in order to survive.

Lakers are found in deep well oxygenated infertile lakes. 

Their preferred water temperature range is between 48^o to 52^oF. 

During late fall, and early spring, lake trout can be found cruising anywhere in the water column.

The rise in water temperature during late spring and summer, will drive the lake trout into deeper waters.

Fortunately for us fisherman, lakers are opportunistic feeders, meaning they are not picky.

One of the best methods for catching lakers is trolling. 

Below are some helpful links that may improve your skills.

http://www.peaceislandlodge.com/lake.htm

http://www.the-fishing-network.com/magazine/v01/n05/tvo-05g0.htm