Make sure the rodent is of the proper size. The width of its body, around the hips, should be slightly smaller than the thickest part of your snake.
Try feeding it at night. Only have enough light in the room to make it so you can see what you are doing.
Offer the prey and leave it alone for 10 minutes or so. If he doesn't take it, remove the prey and wait for the next feed day. Try your best not to handle the snake until it starts to feed for you.
If your husbandry techniques are spot on you should have a good feeder on your hands in a few attempts.