The hot debate right now is what's more important: having a higher rate of BPS or being able to hit what you actually want to hit. To me it's a self explanatory answer: after all, if I can shoot three rounds and hit what I'm aiming at with two of those rounds, not only did I actually hit what I wanted but I used a lot less money doing it. And let's face it: money (or lack of) is probably the number one reason serious players don't get out on the field more. Thankfully having a lot of money isn't a requirement to improving one's aim -- it helps, but it's by no means necessary.
Below are some simple drills that really help. Most can be done alone or in groups.
Take any straight edge -- a broomstick, yardstick, whatever. Hold it like your marker and practice bringing it from the down position (like you hold your marker when you're just walking) and up into the ready position (ready to "fire"). Notice what you see and practice freezing that picture in your head...until you can crystallize what you see in a nanosecond.
Go out in your yard and shoot a few targets-on a string. If you have any trees with a low hanging branch tie an empty soda can to it (say, at a height where your opponent’s hopper might be) and try to shoot the can as it sways in the wind. Hit it three times in a row and you're a winner! Then back away and try it again. Or try smaller targets.
Set up targets and assign each of them a point value, the goal being to reach a certain number of points during the exercise. Using only 50 balls(or whatever number works for you) shoot until you have no shots left-if you reached your point goal treat yourself to something fun! If not, practice some more!
This drill is especially good for teams. Setup an "obstacle course" including several sprints, crawls, and zig-zags. Shooting while moving is quickly becoming a very important part of this sport and it could help make the difference for you. Also, it'll help give you some much needed body consciousness on how you move and how fast in each position.
Play H-O-R-S-E! Yeah, you heard me: grab a friend and play. Have the first player announce a target and shoot at it. If he/she hits it then the second player must as well. If he/she misses, he gets the “H” an the second player shoots. Every time someone misses, they get a letter. The first player to spell horse loses.