Puckouts
Puckouts are among the few opportunities that any player has to plan what's going to happen next, rather than simply reacting to the play. It's very important that you use this opportunity to your team's advantage.
There are two approaches to puckouts: blast the ball as far downfield as you can, or aim for a target. (The two strategies can, of course, be combined.) Being able to consistently send the ball far down the field to your team's offense is a valuable skill, which can lead to quick scores.
If you use the 'aim for a target' approach, there are some things to remember. If you have an open teammate, you usually don't want to hit the ball directly at them; that just freezes them in place, waiting, and gives the opponent a chance to run in front of them and block the ball down. Instead, you want to look for a direction in which your teammate has open space to run and be first to the ball, and lead them there. Even if your target is closely marked, with the person covering them only a step away, that means your teammate starts out with a one-step advantage on a ball hit to their other side. Distribute the ball around to different teammates, especially early in the game; don't be predictable. Keep an eye out, though, for which teammates are winning their battles and which ones aren't. As the game progresses, you'll want to adjust your puckouts accordingly. Watch for plays where the offense has been drawn in toward the goal; if they haven't had time to get back in position before you puck out, there will probably be someone wide open for you to aim for. And look for wide open spaces on the field, which will give the ball a chance to bounce and roll for greater distance.
The mental aspect
Physically, goalkeeping doesn't require any special skills; the same skills which are useful in goal are equally useful elsewhere on the field. Only the mixture is different; goalkeeping, for example, doesn't place so much emphasis on running. It's the mental pressures which set the position apart.
The goalkeeper will spend the majority of the game doing nothing; just watching as play unfolds down the field. This inactivity provides plenty of time to brood over past plays; because, when the ball does come your way, you need to make the play every single time. Any mistake you make will most likely result in a goal; and you'll feel as though you've just let down your whole team. In a close game, you won't be remembering whatever good stops you've made; you'll be chastising yourself over the one play you didn't make.
And you're going to make mistakes; you're going to screw up some easy plays. The first, last, and most important skill for any goalkeeper is the ability to cope with failure. How you do it will vary from person to person, but you need to be able to accept your mistakes and move on. And you need to be able to do it quickly; the next play might be only ten seconds away. You don't want to be so mentally preoccupied with the last play that you mess up the next one because of it.
POSITIONAL PLAY: Keeper