If your work involves regular typing, get a special ergonomic keyboard. The keys on this keyboard are divided into two arms, so that you will not be confused which hand and finger to choose in order to press any particular key. The special design of the keyboard helps keep your hands from getting tired as compared to a conventional or laptop keyboard.
Correct sitting position can greatly facilitate you in order to increase your typing speed. The chair should have a backrest that supports the spine. Your legs should be parallel to the floor and the keyboard should be at elbow level.
Relax your fingers when typing after clicking on the button as stress triggers fatigue and muscle tension. Relax your hand while working with a mouse and try to move not only the wrist but the whole hand. It is highly recommended to play piano, guitar, badminton and tennis in order to strengthen you arms.
If you cannot increase your typing speed with the aforementioned methods, there are many programs and tutorials that can help you. Buy or download any typing program and follow the instructions to increase your speed.
Do not force yourself to learn this art after sitting in front of the keyboard the entire day. Spend around 15-20 minutes a day to help improve your typing speed. Most importantly, try to use all ten fingers on the keyboard.