I piping in for the first time without reading all the other replies.
Personally, I think a big part of the problem regarding slow play lies with the rules and etiquette. They simply don't "encourage or enable" faster play. While I think we all agree with and like playing by one set of rules, I also feel there should be some minor modification of the rules between daily/ club level play and that of higher level amateur and professional play. These minor modifications wouldn't take away from the daily/club play, would have minimal if any impact to golfers' handicaps, and most certainly speed up play.
Lost balls / Out of bounds: Treat both like a lateral hazard or unplayable lie and allow only two minutes search. So, if after searching for 2 minutes you do not find your ball, then if it most likely went out of bounds then you drop as you would have had it crossed into a lateral hazard or if the ball is lost then you drop (as if it was an unplayable lie) in the area the ball is most likely (determined by you and a fellow competitor or you and your opponent in match play) to be lost, adding the penalty stroke accordingly. No provisional ball allowed to be played. If the player wants to hit another from the original spot, whether it is before searching or after, that ball is then in play under stroke and distance. Most of us amateurs will just drop after searching for two minutes. It would probably be the rare case when one would be better off going back to the location of the previous spot and playing another ball under stroke and distance. With ESC already being used the effect on one's posted score and eventually his/her index should be inconsequential. The biggest impact/difference compared to high level amateur/professionals would be in an actual tournament where under rules as described above, a golfer who wins/places in because he/she hit a ball out of bounds once and then proceeded as if it was a lateral hazard as opposed to hitting another one or more out of bounds before actually getting a ball in play.
Turn it is to play: Ready golf needs to be the standard and not just something to which lip service is paid. This also needs to apply to match play accept from the teeing ground and when both players' balls are on the green. No instances where one plays out of turn from off the green "without permission" and holes the shot and opponent says play it over after he/she putts from a longer distance. Under stroke play, honor on the teeing ground should still be honored for the most part, however ready golf should still be encouraged and during tournament or other competitive play, if the player with the honor is a habitual laggard and seldom if ever make his/her way to the tee box in a relatively quick manner he/she should not expect the box to be "his/her's." My philosophy is if you have the honor, act like it by proceeding quickly to the next tee box, ready to play as soon as it's clear.
Play on the Green: Too much emphasis is placed on not stepping on someone's line. With spike marks largely a thing of the past, way too much time is spent tiptoeing around someone else's line, marking one's ball and then in some cases moving the mark and having to move the mark back before replacing your ball and eventually playing one's stroke. Once a player begins putting, whether based on whose turn it is, permitted by playing partners or based on agreed upon ready golf by the group, it should be the rule in stroke play to continue putting until holed out, with a one stroke penalty added for failing to do so. With such a rule, little if any regard should be made to someone else's line, provided you don't intentionally drag your feet or do anything else to cause damage...and if you do cause damage and it's obvious you did, the damage should be repairable by you or any other golfer including the golfer in whose line you stepped before he/she plays his/her next stroke. If a golfer caused damage on purpose and does so on a recurring basis, the current rules already address such a situation.