The game clips come in real handy. Have the clip in the open position, gaff the fish, and slide the clip thru his gill and mouth once he flares his gill. Close it, and put the gaff away, time to bleed the feesh.
I used tennis racket string (think it's near the 250# test range) and tie it to a snap swivel to one of the deck eyelets.
Not that I've ever caught a fish though....
