Being a goalie there are only two different types of saves that you can make. Either a blocking save or a catching saves. The blocking save just hits you and bounces off or drops, and the catching save is where you catch the puck so there is no rebound. It's pretty clear that you would rather make a catch than a block so you can hold onto your rebounds and there will be no second chances. If the puck is in close you don't have much time to react to the shot so you will probably just have to block it. If the shot comes from far out you should always catch it.
When blocking the shot you want to come out nice and far so the puck can't slip around you because there isn't much time to react. Next you want to go into your butterfly when the shot is released to get maximum net coverage. When in your butterfly keep your hands and knees tight and compact to your body and your legs flared outwards to get maximum net coverage. By doing this you will cover most of your net and when the shot comes you make the save, make sure you cover the puck up a quickly as possible.
When making a catching save, always make sure that you have a second piece of equipment behind whatever you're catching with just in case you miss the puck accidentally.