There is an old golf adage of "drive for show, but putt for dough," which basically means a long drive may look great, but it is the putting that makes a person a great golfer. That remains true, but a superior short game is what makes a golfer truly a success. She must be able to handle the pressures and intricacies of getting a ball onto the green, especially since courses continue to get longer and harder to play.
Practice your aim by putting a bucket in the middle of a field and walking about 60 feet away. Use your pitching wedge to hit balls toward the bucket. This exercise will help you build up accuracy, as well as your confidence. It is very tough to get the ball in the bucket, but if you can start getting near it (or in it), your game will improve on the links.
Go to the driving range and put down the woods. Golfers love to go to the range and hit long balls, but that won't help your short game. Hit an entire bucket using just your pitching wedge from the grass. Focus on getting the ball high. Also, many ranges have a sand trap. Take about 20 balls and work on your shots from there.
Use plastic balls in the backyard if you don't have time to go to the range or hit in a field. Plastic balls won't travel far, and you still get the range of motion needed to get better.
Cheat just a little on your swing. Yes, everyone wants a graceful swing on the course, but sometimes a golfer does not need that in the short game. Practice "punching" the ball with a chipper, which is a club that allows the user to take a short half swing and knock the ball up in the air and forward with some accuracy. Some golfers look down on chippers, but they are a great tool to build confidence.
Study the course. Many people with good swings and mechanics still do badly in the short game because they don't think on the course. Look at the layout of the hole and decide if it is better to shoot for the pin, behind the pin or in front of the pin. Know where the traps are around the hole. Only chip when you need to chip. If you can use your putter, use it.