Do you see tracks? If so follow them after a fresh snowfall & set at the Minks den. Sometimes you have to go right to the source. All above info as well, Bottom edge, blind, snow pockets & moving water areas all need to be use where you can.
Most of my Mink trapping is done this time of year, some times starting my mink trapping after Christmas even.
Keep in mind Mink are hungry all the time.
Look for creeks where they start. Its a good place to find open water.
One year I chipped threw 6" of ice to put in a 100 bottom edge sets. Hard work but it was what I did to keep my Mink line going.