Look for trails leading into corn fields, some maybe deer trails, but that doesn't mean coons aren't using them. Pay particular attention to the trails that look like tunnels coming out of brush. Look for tracks and scat.
Look for trails running parallel to streams as well, particularly at the top of a steep bank and also along the waters edge where a sand or gravel bar peters out to a steep bank. That will force them into the water where the bar runs out. Put in a blind set there for sure!
Any place that you determine is good enough for 1 set, put in at least 3. If it's LOADED with sign and you immediately think "I need at least 3 sets here!", put in 5-6. Coons travel in groups alot and want to have traps ready to catch them when the come through!
You're going to get the occasional oppossum, muskrat, mink, and maybe even a fox, plus incidentals (cats, dogs, squirrels, etc) in some of your traps, and you don't want them "plugging up" all your steel when the coons come through.
Set a place for a week and then pull out and move on unless your still consistently catching. Just get the cream of the crop, and move to new turf. And don't just move to the opposite side of the field, move to a different property where you're targeting new coons. Coons are smart, once they figure you out, it doesn't matter how long your traps are there, chances are, you aren't going to catch one of the ones that's onto you.
"Knowing when to shoot and when to wait is one sign of maturity in a bowhunter. Be patient and pick your aim point carefully." ~ Randy Ulmer
"I suppose it's the way of hunters. We are very odd fellows." ~ Peter Hathaway Capstick