accuracy is a lot better than speed. Speed will come with confidence. I approach all beginners the same. Beginners, therefore I don't let them hammer against the anvil. I use short 2x4s and mark a spot for them to hit. This gives them a visual of what the hammer is doing and how far off the mark they are. After they have mastered hitting the mark then they can develop proper techniques like tilting the hammer head, offset blows, etc. Light weight hammers are preferred at first until they develop strength. Using the boards has always helped me in getting people to hit accurately with confidence.