Practice does not make perfect, perfect practice makes perfect.  This video shows you the shooters illusion and why we want to bring this up is when you practice shooting its good to practice all 4 corners and the 5 hole, but its most important to practice 60-70 percent of your shots to your forehand side. What the video shows how you see the goalie and net from your eyes is not the same as what you see when you look at it from the puck/blade of your stick. You may see top left corner is open but in reality its not necessarily the best place to shoot. Its important to work on all the shots, but make sure you practice more shots to your forehand side. Right handed shots should shoot more pucks to the right side of the net, left handed shots will shoot more to the left side of the net. Practice does not make perfect, perfect practice makes perfect. 
When you are ready, 100 pucks a day. If you do not have a shooting area, ask a friend who has a tarp to work together. End up playing a game after you get your work in, call your shots, play H-O-R-S-E by calling your shot and making your opponent match your shot. If you keep up with consistent shooting practice there is no doubt you will become a more accurate shooter and increase your shot speed. Get a note pad and keep track of how many shots you take. Watch the video below