Why Should I Learn To Type?

Posture

Sit straight, and don't slouch in your chair. Keep your feet level on the ground, and have your monitor (if possible) 20 inches or so away from you.

The Home Row

The home row is insanely important! Keep your fingers on the home row at all times, and return to the home row after you press a key.

Don't Rush!

Don't rush while you type! Rushing to get a fast WPM does more harm than good. While maintaining a steady speed, you may type slightly slower, but your accuracy and precision will be much higher than compared to the former.

Don't Constantly Move Your Hands

While you type, keep your hand movement limited. Some movement is okay, but by moving your hands across the entire keyboard while typing can be harmful to your hands.
By limiting movement in your hands and fingers while you type, will reduce stress and improve your typing speed and skill.

Take. A. Break.

It's extremely important to take a break every now and then while you are typing, and especially while you're sitting at your computer.
By taking occasional, or even frequent breaks, you reduce the amount of stress on hands, wrists, and even your entire body.

Take It Easy On Your Keys

As you type, don't mash down the keys with all your might. But instead, quickly (but firmly) press the key. You increase your rhythm/WPM, and you don't potentially harm your keyboard in the process.