Typing is one of the best skills I have ever learnt. I learnt using Mavis Beacon Typing Tutor. I worked on accuracy for a long time and later came the speed. At the height of my typing I was getting upto 85wpm. I then developed mild RSI and to prevent further injury and damage reduced the amount I typed and the speed. Luckily I haven't been permanently affected by all the years I've been typing and I put that down to the training and practice of typing because you learn that you don't need to hammer the keys to be fast and accurate.