Both. Lag closer, and make more shorter ones, but lagging closer might be more important. 3-putts from 30 feet should be reasonably rare, from 20 feet should be really rare. If you're trying to hit a putt 3 feet past the hole, and you hit it 3 feet longer than you intend, you have a tough second. If you're trying to die the ball into the hole, and you're 3 feet long, you have a very makeable 3-footer. Once you get past a certain distance, maybe 12 to 15 feet, your speed goal should be at the hole, not past it.