Observe first for low hanging mist/fog in the morning. Before hand determine the predominant type of insect (Callibaetis/Hex, etc) and baitfish/crayfish/frogs activity and fish found in that area/lake. Observe for hoppers, flying ants, damsels and dragons in the air as well as scuds, and other non flyers etc with a few passes of a small mesh seine in the weeds. Give priority to down wind sides if the wind isn't too severe for fishing and to inlets and then the outlet. Give priority to south facing sides in early season as these warm first. Look at the surrounding topography to gain insiight to the contours likely found in the lake. If the lake is man made look for old roadbeds crossing, rivers and creek transects, etc. Of course look for rises and riseforms. When all else fails slow troll a Black Wooley Bugger on a sinking line as you paddle about, gaining insight.