Technique is very important when you are learning how to type. Keep your fingers hovering over the home row of keys, and move only your fingers instead of your entire hand when typing. Hit the keys gently and at a steady pace to type quickly.
Posture when typing is an important key to typing correctly. Sit straight up and have your feet flat on the floor.
When typing it is important to keep your eyes on your screen or the paper you are typing from rather than on the keyboard.
The best way to improve your typing technique is through practice. You will not learn how to type effectively over night, it is a process that requires patience and practice.
Typing correctly is a definite up-side to many things. If you can type correctly and quickly, things will be done at a faster pace. It could put you ahead of another applicant for the job with equal training and the only difference being that you can type. Along with the benefits of typing correctly, there is also many reasons why typing incorrectly can cause problems in the long run. Diseases such as DeQuarvain's disease can be caused by typing to much/incorrectly.
When learning how to type, you will make mistake after mistake after mistake, but how you see those mistakes will determine how fast you will learn to type. If you see all mistakes as a problem or terrible things or something that you did wrong, it will make typing more boring than it already seems, but if you look at those mistakes as opportunity to improve then you will want to improve and typing won't seem as bad. It will give you something to look forward to.