When lake trout are in the shallows in the spring time, anglers will cast a variety of lures to find active fish. Since most anglers plan fishing trips in the summer up north, many anglers will never get to have a lot of success by casting the shallow and mid-depth ranges. They will typically be jigging or trolling for them in deeper water. If you can get up north when water temperatures are still cool, you can cast for them similar to how you would fish for bass or northern pike, which can be a lot of fun.
Jigging is probably the most popular method for targeting lake trout, especially up in Canada where these fish can school up in huge numbers in deep water.
Trolling is also very effective and how most anglers target them in the Great Lakes. You can troll up north too and have a lot of success. You just have to make sure to get your baits down the right depths. You may have to use downriggers to get your baits down there.