Almost everyone can benefit from typing faster and more accurately. Computers are a part of everyday life, and it is suprising how many people have not taken the time to learn the proper keyboarding technique. Touch typing - using the proper fingers for each key, and not looking at the keyboard while you type - is a skill that is learned with practice.
A study by Vanderbilt University in 2013 showed that most advanced typists could not write down the correct location of the keys when shown a picture of a blank keyboard. See the article here. When you think about this, it makes perfect sense. If you have to think about where the keys are while you are typing, you are probably not typing very fast. Touch typing is learned with repetition, not by reading a book.
With that said, there are a number of ways to improve your speed once you have mastered the basic skills. The most important thing that you will need to learn is the proper typing posture. There are thousands of injuries every year from stress related to typing. You should also remember to take regular breaks. If you have nothing else to do, just look away from the screen for a while. It is recommended that you take at least a 10 minute break every hour.
Other major factors are patience and determination. Don't expect your speed and accuracy to jump overnight. If you practice your typing regularly, and pay attention to your common mistakes, you will see results. I know it is hard to get 'excited' to practice keyboarding, so unless you have a job interview looming you don't need to force yourself to type constantly. When you are feeling motivated, do 20-30 minutes of practice tests or typing lessons. Focus on your accuracy first, and the speed will come with time.