Dropping procedure: When taking relief (from an abnormal course condition or penalty area, for example), golfers will drop from knee height.

Measuring in taking relief: The golfer’s relief area will be measured by using the longest club in his/her bag (other than a putter) to measure one club length or two club lengths, depending on the situation, providing a consistent process for golfers to establish his/her relief area.

Removing the penalty for a double hit: The penalty stroke for accidentally striking the ball more than once in the course of a stroke has been removed. Golfers will simply count the one stroke they made to strike the ball.

Balls lost or out of bounds: Alternative to stroke-and-distance penalties: A new local rule will be available in January 2019, permitting committees to allow golfers the option to drop the ball in the vicinity of where the ball is lost or out of bounds (including the nearest fairway area), under a two-stroke penalty.

Elimination or reduction of “ball moved” penalties: There will be no penalty for accidentally moving a ball on the putting green or in searching for a ball, and a player will not be responsible for causing a ball to move unless it is “virtually certain” that he or she did so.

Relaxed putting green rules: There will be no penalty if a ball played from the putting green hits an unattended flagstick in the hole, and players may putt without having the flagstick attended or removed. Players may repair spike marks and other damage made by shoes, animal damage and other damage on the putting green, and there is no penalty for merely touching the line of putt.

Relaxed rules for “penalty areas” (currently called “water hazards”): Red- and yellow- marked penalty areas may cover areas of desert, jungle, lava rock, etc., in addition to areas of water. Expanded use of red penalty areas where lateral relief is allowed, and there will be no penalty for moving loose impediments or touching the ground or water in a penalty area.

Relaxed bunker rules: There will be no penalty for moving loose impediments in a bunker or for generally touching the sand with a hand or club. A limited set of restrictions (such as not grounding the club right next to the ball) is kept to preserve the challenge of playing from the sand. However, an extra relief option is added for an unplayable ball in a bunker, allowing the ball to be played from outside the bunker with a two-stroke penalty.

Pace-of-play support: The ruling bodies will reduce the time spent searching for a lost ball from five minutes to three; there is an affirmative encouragement of “ready golf” in stroke play;

Source, GolfWeek: https://golfweek.com/2018/03/12/new-rules-of-golf-unveiled-set-for-2019-debut/

THE PUTTING GREEN

If you accidentally move your ball or ball-marker on the putting green, there is no penalty. Just put it back. Currently: It’s a one-stroke penalty if you do either (with exceptions).

If you’ve lifted and replaced your ball on the putting green and it moves, move it back to its original spot no matter whether wind moved it, or there was no clear reason. Currently: The ball is played from its new location unless it was moved by you or an outside agency. Then it would be replaced. So long as you don’t improve the conditions for your stroke, you can touch the line of putt to indicate a target. Currently: Touching the line comes with a penalty of loss of hole (match play) or two shots (stroke play).

BALL AT REST

You are only considered to have caused your ball to move if it is virtually certain (at least 95 percent likely) that you were the cause. Currently: You are consider to have caused your ball to move if it is more likely than not (50.1 percent) that you were the cause.

No matter where you are on the course, there is no penalty if you accidentally move your ball while searching for it. Just replace it. Currently: There is a one-stroke penalty for accidentally moving it. If your ball is lying off the putting green when it moves, and its original spot isn’t known, you just replace it on the estimated spot. An example: If your ball was buried in matted-down grass, replace it in the estimated spot, buried in matted-down grass. Currently: You would drop when you’re not sure of the location.

BALL IN MOTION

If your ball accidentally strikes you, your caddie, your opponent or any equipment, there is no penalty. Play it as it lies. But you cannot deliberately try to carom a shot off your equipment. Currently: Accidentally hitting yourself, your caddie, the person attending a flagstick on the green—or an attended or removed flagstick when making a stroke from the putting green— resulted in a one- or two-stroke penalty depending on the circumstances

Source, GolfDigest: https://www.golfdigest.com/gallery/a-comprehensive-guide-to-the-new-rules-of-golf