Well it all depends on what style you perfer to play, each type of goalie can be successful at breakaways you just need different skills. There are some goalies I've seen that sit almost inside the net, and still can stop their fair share of breakaways, while ive seen others rush out to almost the bottom of the circles. The key thing is making the shooter make the move and reacting, its alot easier for a shooter to correct himself after you force the hand than it is for you to react to a deke while you are lying on the ground. You also have to be agile enough to go post to post while keeping the 5-hole somewhat protected, I can't even count how many moves the shooter goes post to post. The last thing is a bit of luck, sometimes you'll do everything right and still will find the tiniest of holes and others not and of course there is the time you'll do nothing right and you'll throw a miracle leg pad at it and bat it away...
Location: Halfway between Nothing and Not Much Else
The fundamentals always stay pretty much the same. Focus on the puck and the puck alone. If you can do that the shooter can drop shoulders, kick his leg whatever he wants and it shouldn't fool you. (And if he tries that cute little one-handed drag he will look pretty foolish; always a bonus) Remember you're not stopping him, you're stopping the puck.
Gap control as previously mentioned if you like to challenge. If you back in too slow the shooter can go around you, too fast and you give up the easy shot.
If you're playing a less-skilled league, the shooters will often give away what they're doing when they cross the blueline if you know what to look for. If the player is carrying the puck in front of him, it's almost always a deke, they can't get anything on the shot when the puck is in front of them.
If it's to the side then you have to be extra patient because shots or dekes are possible. Patience is everything.