Food is the primary concern of all fish, and their existence is entirely dependent upon obtaining enough to survive. Knowing what a fish prefers to eat at all given times of the year and presenting artificial lures & live bait to them in the most natural fashion is vitally important in order to fool and catch 'em consistently!
Comfort is the second most important fish priority. Each fish species has its own comfort zone, preferring certain bottom types, water temperatures, light conditions, depths and cover areas. Clean hard bottom with firm sand, rock, gravel and weedbeds are generally characteristic of good fishing habitat, while areas of mud and silt are often barren and should be avoided. Fish often avoid sunlight, so spend your time looking for deep, dark water during the bright calm days then the sun's rays penetrate deep; or look for shaded areas of weeds, submerged stumps, timber, sunken logs and docks. Light penetration varies with wind effect, sky conditions and water clarity; so don't waste time in water that contains too much light! As a rule . . . fish inhabit areas just below the sun penetration point!
Safety is the third primary concern of fish, and therefore search for areas that have depth or heavy cover very near their home and feeding flats. Fish use vast open areas of deep water, weeds and underwater obstructions to escape from predators. All fish display a schooling instinct & travel in schools when hunting for food or when moving from one area to the next. After catching a fish, always mark the spot exactly . . . and work it over thoroughly!
Fish have a natural instinct to spawn & reproduce young. This annual spawning ritual is primarily controlled by water temperature. Prime spawning areas include rivers and streams with current, rocky shorelines, black bottom bays, sloughs, boat canals, and protected weed & reed flats.