Use Your Feet
When teaching workshops, one of my first pieces of advice is to look around and observe well before setting up to take photos. That same advice applies to location scouting. Walking around and spending some time to take in a location’s features can help in identifying subjects and compositions that might be more compelling than what first caught your eye. This kind of exploration can also help you get a sense of how your perspective changes as you move around. With more information about a place, you can make better decisions once you start photographing.
Look Through Your Lenses to Help Plan Possible Compositions
With practice, a photographer can get a sense of what a scene might look like at different focal lengths. Still, I find it to be helpful to get out my camera and lenses when scouting to see what actual compositions might look like. I sometimes find that what I think looks great to my eyes looks far less interesting when I actually take a look through the lens I intend to use. I would rather know that a concept will not work while scouting rather than returning during better conditions only to find out that my idea doesn’t translate very well into a photograph.