Take time to study each new body of water. Polarized glasses can help you find deep water and underwater structure. You will see more from a high vantage point. Lakes with the fewest fish often hold the largest individuals. Many lakes can appear dead at midday, only to come alive in the early morning or evening.
Some lakes have extensive shallows where fish cruise on their search for a meal.
The best strategy in this situation is to find a vantage point where you can see fish approaching, then place a cast in their path, but well ahead of them. Let your fly or lure rest on the bottom until retrieval brings it across their line of sight and about 5 feet in front of them. Generally these fish have a route that they will follow time after time. Fly tackle is the most effective way to quietly present an offering without disturbing wary trout. It is the method of choice when fishing shallow water or casting to fish close to the shoreline.