How can I safely hammer? is there a technique?

Try the Tap 'n Go technique: Touch the nail head with the hammer head, pull the head back and then use force to hit the nail, repeat by touching"p>

Safety with hammering may include holding the nail with a needle nose pliers, folded paper, piece of cardboard or your fingers. If you have usable vision, you may want to wrap a strip of colored electrical tape around the head of the hammer so that you can see where the hammer head is going. Most hammers are steel, which would look dark; you may want to choose a tape color like white, yellow, red etc. Or your may want to put a color that you can see on the nail head, e.g. white, red, etc. Avery-Dennison "see through" removable colored dots work well here and are easy to remove from the nail head when you are done. Find Avery-Dennison "see through" removable colored dots at InstaOffice .