My husband has killed over 20 in one year, and usually averages around a 12-15. He's darn good at it but it takes patience and time.
He can work from home whenever he wants and takes frequent trips into the garden. He studies it. If he sees a new trench he immediately grabs the hose and plunges the running hose into the trench (which is easy because the earth is very soft where they've dug. He then waits. He may have to move the hose further down the trench if the mole doesn't come up within say 5 minutes, but the mole will have to come up (if indeed it is a fresh trench - if not - he probably has moved on to somewhere else). Once the mole emerges - he stabs him with a knife. Brutal. I can't watch it. Hubby doesn't enjoy it - hates it in fact, but nothing else has worked (not moth balls, not stink bombs, not traps).
So far (knock on wood) we haven't had any moles in the yard this year. We're watching though.