How do people get to type 60-100 words per minute? It does have something to do with practice but not completely. Some people will just never reach those speeds. It's like chess, math, and playing a musical instrument. You could be doing it for years and still not be significantly better at it than someone who learned it efficiently in a much shorter period of time. That's not to say you wont improve by practicing, but each system has its limitations. Bad habbits are hard to kill, so it's always better to learn things slowly but efficiently.
There are a few ways to increasing your typing speed efficiently. The problem is that they require your time and a lot of frustration since you can likely type fast now on your current system. You're going to have to type slow again to practice. You can try typing software like mavis beacon or free software from sourceforge to practice. To prevent fatigue you want to let your strongest fingers: index, middle, and ring; do most of the work. The standard placement of your fingers is, left hand on asdf, right hand on jkl;, with both thumbs on spacebar.
By far the most efficient method of increasing typing speed is using the dvorak (',.PYF) keyboard layout. It's a different order of the keys than the standard QWERTY. Most versions of windows and linux have the options to switch between the standard keyboard and dvorak keyboard. To change it and try go to start->control panel->keyboard->regional settings and select dvorak. I couldnt find it there, or in accessibility options, but I found a freeware program that quickly switches between the two by just double clicking it in the task bar. There's also a useful program called keytweak that will let you manually set what keys you want where.
If you switch the the dvorak method expect it to take you 40 hours of typing to really do well. People actually learn the dvorak keyboard much faster than the standard keyboard, but still, it will be very frustrating at first, especially if you're like me and have been typing on the same layout for years.
For those that have to work in an office every day without the option of resetting the keyboard, it's not recommended. The Dvorak keyboard is better than password protecting your computer. Most people steal your password by infecting your computer with a program that records keystrokes. Having the dvorak mode will prevent script kiddies from causing you problems. Again I should reiterated, for the few hours of typing time you'll struggle, you'll save yourself a lot of wrist stress and small bits of time everyday for years. This is a MUST-DO for all bloggers or anyone that works with medical transcription/jobs that deal with typing to make money.