Put some light grease, or preferably moly -grease, on the sear and hammer notch. Then put light thumb pressure on the hammer while pulling the trigger. Do this 40 or 50 times, and it will make the trigger feel much smoother, and usually eliminate most of the creep. Do this with the gun broke down, and use your other hand to stop the hammer drop. Use a glove on both hands to avoid fatigue. You can also do it with the gun assembled, but use a thick piece of rubber inner tube to cushion the blow against the firing pin/bolt. Best to remove the firing pin too. Or just catch the hammer with your other gloved fingers / hand. This smooths out the mating surfaces of the sear and hammer.
Hope this makes sense? I've used this trick on many guns with exposed hammers with good results. Never do it on a S&W or Colt double action revolver, or you'll bust the full cock notch.