These fish compete aggressively for any available feed and expect most anything which enters the environment to be eatable, which is why you will find filters from cigarettes in their stomach as well as twigs and other debris. As they acclimate to their world, they will seek out proper food and habitat, which for the first couple of weeks make them easy to catch.
Follow these five rules for trout fishing:
1. Fish where they are, not where they ain't: Hatchery trout will be found in the top four feet of water or in the shallows initially. As they get used to their living space, they will seek out that ideal temperature of about 55 degrees to live and feed in. Generally, if you see fish on the surface, fish there. If you don't see them on the surface, they are feeding on the bottom or somewhere in between, find them. Ten percent of the fishermen catch 90% of the fish, because 90% of the water holds few or no fish. Start out shallow, then work deep.
2. Match the hatch: Find out what the fish are feeding on and try to give it to them. Early in the season, they will feed on nearly anything but as the season progresses you will have to search for the proper food item. I like to troll a streamer fly on the surface or a small, thin bladed spoon early in the season. You don't need fancy gear to do this and you may be amazed at the results, I was when I first tried it. As the season goes on, the fish will look for that ideal water where most of the good feed is and I will fish either a sinking fly line with a nymph or a chrionomid or will fish power bait or eggs on, or close to, the bottom. Remember the way a fish head is shaped, they look up, not down, so present the bait or lure in their field of vision.
3. If what you are doing isn't working, change what you are doing: This is a simple rule often broken. We get used to one or two methods, which have worked in the past and won't change when they do not work. The opposite of this rule is "if someone else is catching fish, find out what they are doing". I never hesitate to ask when someone else is catching fish. They will usually tell me and if not I will watch them until I figure it out. If the fish are there, you can catch them.
4. Use persistence, not patience: This is similar to rule number 3 but slightly different. Patience is fishing the same unproductive method or the same unproductive spot. I seldom fish a spot on a lake for more than 1/2 hour if I am not catching fish. I have found (and shown other people) that a move of as little 20-30 feet can make the difference of catching or not catching fish! Change until you do catch fish!
5. Keep it all in perspective: Remember, you are out to have a good day and catching fish is just a great bonus. If for some reason the fish are not biting and you cannot find a way to get them to bite, enjoy the day on the water, the company and the snacks (always have snacks). There will be another day to fish.