Tiger Woods has often said that the #1 key to good putting is hitting the ball in the middle of the clubface. If you can't hit it consistently solid you can't control the pace and if you can't control the pace you can't control the line. The way Tiger Woods constantly hits it solid is by practicing and warming up with the Gate Drill.
Tiger rests the heel of his putter against the inside edge of the “heel” tee. At that point there's really not a lot of room left between the toe of his putter and “toe” tee... maybe 1/8”. He places these two tees about four feet from the hole.
He likes to start this drill by hitting putts with just his right hand. He’ll hit at least 20-30 putts this way. He’s simply trying to get a feel for the face rotating and feeling the right hand “hit.” He wants to feel a “load” (weight of the clubhead) in his stroke going back and a “release” coming through.
After doing enough of these where he feels comfortable, he'll add his left hand and try to simulate the same feel with both hands. If it's not quite right he’ll bounce back-and-forth between his right hand and both hands until he does.
When he's satisfied with the “feel” he’s looking for, he’ll hit a few 6-7’ footers and then move on to lag putting… slowly ramping up his speed.
His ability to own this free flowing stroke, where he feels the weight of the clubhead load and unload, but while still holding it through a little bit is unique and makes Tiger the great putter that he is.
So here's this guy with this amazing touch and feel but still having the ability to hit the ball in the same place and launch it with the same amount of loft every time. He strikes it this way and launches with nearly 4° loft every single time!
Tiger has said: “There is no sweeter feeling than having the putt hit flush and released… that’s such a great feeling.”