Star-nosed moles are by far the number one mole we do in our service area. First off, look at the equipment you are using. We've had zero success using the Victor Out-O-Sight and spear type mole traps. We've caught a few with the molenators, but our number one trap by far is the NoMole trap. If you are using the molenators, I'd recommend getting the Mole Tunnel Pilot from Bob Jameson at
http://www.jamesonsultrablend.com/Mole-Tunnel-Pilot.html before replacing them. This tool makes it easier to bed the trap properly thus increasing the catch success and is a cheaper option than just replacing the equipment. If you're using the OOS or spear trap, you'll have to get new equipment.
When it comes to location, it is key to set the travel tunnels and not the feeding tunnels. This can be more tricky to determine with Star-nosed moles as the tend to travel above ground frequently, but like most mole work look for the longest, straightest tunnels (even if they are only 3 feet long with no other tunnels close by) and don't overlook tunnels coming out of mulch beds.