There are many systems of shorthand. While the more well-known and traditionally taught one is Pitman, there are also the Gregg shorthand system and the Teeline system. Each has its own strengths and weaknesses. While Pitman may overall be the fastest system when learned, Teeline was aimed at those wanting to study from home. Gregg's advocates claim that Gregg is taught in more than 95 percent of the schools currently teaching shorthand in America.
The best way to get faster is through practice. You can either record or download drills to help you get faster. Many of the drills you can find will start off slow and get faster. They may start off by reading letters before listing words and then moving on to sentences. You can record these yourself to help push yourself to just the right level. Make sure you use different drills so that you are well rounded.
If you are planning to build your speed in shorthand, it is important to have a comfortable pen. Try different pens before settling on a favorite. Several factors will make a pen suitable for shorthand work. First, as speed is important, the pen will need to be reliable. The ink should flow steadily, as blank spots may make the work illegible. Also, the pen should be extremely comfortable to hold if you will be using it for long periods of time.
The best way to know how good you are at shorthand or how much you need to improve is to have a goal. First see how fast you are going and then find out how fast others go. If you feel like you can go faster, then set a realistic goal for how fast you want to go. If you are already faster than many of the other shorthand writers you know, then you may not be able to improve exponentially and will have to set smaller goals.