The biggest thing is relax and don't get rattled after a few goals. Keep calm and go back to you're usual reads. Don't try to do too much because that's when you'll start letting in weak ones.
For deflections, one key factor is depth. Compared to 15, you have to be a tiny bit further out of the crease for point shots (about one-third to half-way away from the goal line.). This isn't necessarily to stop the shot because you can stay pretty deep for that, but to cut down the angle on a deflection. Another factor is make sure you drop to butterfly as the shot is taking place, especially if there is traffic front. Eliminate the 5-hold chance on a deflection, you'll get better animations if the deflection goes blocker glove instead of standing up, AND you'll already be prepared for a rebound since you're in the butterfly.
Last but not least, the worst deflections come from shots that aren't even close to the net. Those we really don't have much control over. If you can notice the shot missing wide, just do your best to react and move that way with the LS.