How do I drop a ball correctly?

Under Rule 14.3:

1. You must drop the ball yourself (not your caddie or partner).
2. Drop it from knee height, meaning the height of your knee when you're standing.
3. Let it fall straight down without throwing, spinning or rolling it, and it mustn't touch your body or equipment before it hits the ground.
4. It must land in, and come to rest in, the relief area for the Rule you're using.

If the ball rolls out of the relief area, drop again. If it rolls out a second time, place the ball where it first touched the ground on the second drop.

Playing from the wrong place (Rule 14.7): if you play a ball from somewhere the Rules don't allow, it's the general penalty (2 strokes in stroke play). If it was a serious breach (you could have gained a significant advantage), you must correct it by playing out the hole from the right place before teeing off on the next hole, or before returning your card on the last hole, or you're disqualified. If you're not sure whether it was serious, play out the hole with both balls and report it to the Committee.