DO IT RIGHT, DO IT WRONG, BUT DO IT. Squeeze your eyes shut and jump. Because a wonderful thing happens then. Your focus shifts from yourself, your nervousness, and your imagined inadequacies to the task at hand.
If nature has made you for a giver, your hands are born open, and so is your heart; and though there may be times when your hands are empty, your heart is always full, and you can give things out of that--warm things, kind things, sweet things--help and comfort and laughter--and sometimes gay, kind laughter is the best help of all.