Trout feed mostly on insects (nymphs, emergers, adults). Ofcourse, the big trout need bigger morsels.
My experience with trout fishing, is through fly fishing. Though my first trout was taken on powerbait, used with a spinning rod. Powerbait is a dough like material (is pink/rainbow colored, and can have some glitter).
http://www.berkley-fishing.com/prod.php ... p=PURSTBGC
Observe if the trout are feeding on the surface, or sub-surface.
If you cannot spot the trout feeding, they are most likely feeding on nymphs close to the bottom of the river/stream.
If you do not have access to fly fishing gear, you can use a spinning gear along with a plastics bubble float. Tie a nymph fly (size 14 Hare's ear is a good one) to the other end. Also tie two small lead shot (BB size) about eight inches from the fly. This will keep your fly close to the bottom.
Faster water will require more weight to keep the fly near the bottom. Best thing is to start with two split shots. You can add/remove a split shot depending on the water flow/current. You can also change the size of the split shot.
The line/leader length from the bubble float to the fly should be about 1.5 times the water depth. You should be able to adjust the bubble float, depending on the depth you are fishing. If you keep on hitting the bottom frequently, you need to move the float upwards.
Cast directly across, and allow the fly to move downstream. Keep a tight line to the bubble float, and watch for the slightest movement of the float.
A trout will take a fly, and spit it out in an instant. So at the slightest hesitation of the float, strike.
In running water, a trout will generally lie behind a rock/boulder facing the current. This provides it with protection from the current, and it can also observe food flowing down with the current. You need to identify such locations, by the disturbance on the water surface. Cast your fly/lure so that it moves along such submerged rocks/boulders, where it can be seen by trout behind a rock/boulder.
For the lake do not use the split shot. You need to use a plastic flaot which you can half fill with water. This will help you to cast.
In a lake, it would help to have a small boat/canoe. I use a float tube for lakes. Else you are restricted to fishing the shore. In a lake, you need to give action to the fly (retrieve, pause, , retrieve .......). Mostly the retrieve is only 4-6 inches. Vary the retrive to see what works. The retrive would imitate a nymph (e.g mayfly, caddisfly) moving in the water.
Catching trout in a lake is more challenging, than catching one in running water. This is because in a lake, the trout has all the time to observe the fly. In fast water, a trout has to make instant decisions. The faster the water, easier it is to fool a trout.
In 1996, I spent a month on a work assignment, at Hindustan Photo Films factory in Ooty. Did not have my fishing gear with me, but did go out to fish with a local to Pykara. I remember catching some small fish (no trout). Came to know later, that there was good trout fishing at Dodabetta.