This comes from a very good rules blog by Barry Rhodes
6. Learn how to use Rule 3-3, which permits you to complete a hole with two balls when you are faced with a situation where you are doubtful of your rights or the correct procedure. It is surprising how few golfers are aware of this ’get out of jail card’ and gamble on an option that may cost them a penalty, or even disqualification. Click here for my blog on the subject.
5. Never touch your ball in play without marking it first. There are several occasions when the Rules do not require a ball to be marked before it is touched (e.g. if you have deemed it unplayable), but if you get into the habit of marking your ball first you will not have to remember when you can and when you cannot.
4. Read the Local Rules before playing. See this link for my blog outlining many reasons why this is important.
3. Always determine where the nearest point of relief is before you lift your ball, as it might be easier to play the ball as it lies rather than having to drop it in a potentially worse lie. I have often witnessed players that are so focused on the fact that they are able to take relief from an abnormal ground condition or immovable obstruction that they pick-up their ball before realising that the nearest point of relief is in deep rough or on a steep slope and that they would have been better off playing their ball as it lay.
2. Implement a trigger routine to use every time that you are asked to move your ball one or more putter heads to the side. Not replacing your ball where it was originally marked on the putting green costs you a penalty of two strokes in stroke play or loss of hole in match play. Two examples of trigger routines are; i) to always use one side of a two-faced, customised ball-marker for normal ball-marking and the other, ‘wrong’ side, for when you have moved it to the side; and ii) holding your putter by the head rather than the grip until you reverse your ball-marker placement.
1. Put personal identification marks on every ball that you play - I repeat every ball that you play. I have been using the same red dot formation on all of my golf balls for some years now and it is a long time since I last played a wrong ball. Make sure that you put enough markings on your balls that you can easily see at least one of them, even when your ball is lying in deep rough. Also, you might consider drawing a line around the entire circumference of your ball. This can certainly assist you to line up your ball on both your line of putt and your intended line of play from the teeing ground.