I've never found a better scheme than "leaning in" although there is a whole lot more to it than simply leaning in. It starts with the stance - we want the linemen's feet as wide as possible - if the blocking goes right - no one is coming up the middle and the only chance the defense has for a block is a speed rush off the edge, so we want to make that track as long as possible. We tell the snapper to get his feet set as quickly as possible, then the Guards off him, then the Tackles off the Guards, etc. Once their feet are set (as wide as possible), the holder verifies that we have 11 and everyone's set and the kicker is ready, then he calls, "Set" and then he flicks his fingers to the center to signify that he's ready. (We work with the snapper to ensure that he varies how quickly he snaps it after the signal - the last thing we want is the defense to time their charge off the signal - we tell the snapper that the signal is simply an indication that the holder and kicker are ready for the snap - it is NOT a snap count or anything similar that requires an immediate response - we expect the snapper to then take a deep breath or two before delivering the snap - if the snapper delivers the snap within a half second or so from receiving the signal in practice, there are consequences (up-downs, push-ups, etc.) so this rarely happens more than once or twice.
The linemen stay in a two-point stance (we've also done it from a three-point with about the same results) - at the snap, they step inside with their inside foot behind their inside teammate's outside foot. They also drive their inside shoulder into their neighbor's hip, creating an impenetrable wall. We go to great lengths to teach them that they are covering an area, NOT blocking a man. Yes, they are going to get hit, maybe even cheap-shotted, but they need to hang in there and make the block - they can get even later (between the whistles!!). They keep their outside foot in place ("locked in cement" is how we describe it to them - this is critically important, their natural instinct will be to step into contact with both feet, but if they move that outside foot, it creates a lane for another defender to block the kick - that outside foot MUST NOT MOVE). That is the case for the Gs & Ts (the snapper just worries about snapping the ball and then gets to the ground if there is violence around him). The Es step inside the same as the Gs and Ts, but they can't commit totally to the inside like their interior counterparts - they have to cover the inside first, then make sure no one is trying to go outside them as well. The Wings line up with their inside foot even with the E's outside foot, but about a foot behind it (aligned at about a 45-degree angle to the outside). They also keep their outside foot "locked in cement" and step inside with their inside foot, making sure they lock down the shortest, inside route to a kick-block first. Once the inside threat is eliminated/contained, hopefully the wing still has enough left to give a shove to any outside rushers to slow them down. Even without that, it should be enough to get the kick off, but we want to slow everyone down as much as possible - all it takes is a slightly off-target snap or a sloppy hold and that timing is thrown off and a rusher that would normally never get there suddenly has a highlight video kick block to show off to everyone at your team's expense.
The ends and the wings must keep an internal clock as well as listen for a "Fire" signal. If they hear "Fire" or if more than 2 seconds have passed since the snap, we tell the ends to go towards the back of the end zone (assuming this is a PAT) and the wings to release to the flat just across the goal line. If it is a bad snap, or if the holder mishandles the snap, we want the holder to pick up the ball, then reverse pivot (i.e. turn towards the inside and away from the line of scrimmage) then look first to run to the end zone, or throw to either the wing or the end if the run isn't there - what we don't want the holder to do is turn forward towards the line of scrimmage - that will turn him directly into the rush of the edge defender and cause a large collision and loss of yardage (generally also a turnover on a down where you're attempting a field goal), so you want to be sure to drill your holder to turn away from the line of scrimmage if he's picking up an errant snap.
