You will need some elementary comprehension of the art of throwing knives before you actually will be capable of throw them correctly. Obviously practice is likely to make perfect in the proficiency of efficient knife throwing.
A good way to begin is to keep your training sessions short. Start with just fifteen minute long practice sessions. To avoid losing focus and getting too tired this is very important. Then your practice will become very counter-productive.
To really get good at throwing knives it helps to be in excellent physical shape. You will probably find that when you first start practicing that you might be too weak to throw effectively. Especially your fingers will be very weak. The upper body is very important to exercise and make stronger. Strength training frequently as you can will help a great deal.
Every day you should try to do at least fifteen to thirty five push-ups. Doing push-ups and other excersises will help you build up your upper body strength, which will help a great deal in throwing knives. And one thing that many beginners find is that their fingers are simply too weak. So you may want to use springs and finger weights until you feel confident of your grip and throwing of the knives.
Using the proper stance is rather important when you actually throw your knife. Your right foot will be behind your left one, basically in somewhat the same manner as you throw a baseball. Keep both of your knees bent with the front one bent a bit more than the back one. Your back foot is where you want most of weight to be focused on.
Keep both of your arms straight and pointed toward the target you are aiming at. Then bring back the throwing knife even with your head in a smooth motion and throw it as if you were chopping something right in front of you, like a tree branch. Your weight should start on the back foot and be shifted forward to your front foot while you are throwing the knife.
As your arm and the knife align with the target, this is the time when you release your fingers, let them snap back and throw the knife. After you let go of the knife your arm should keep on going down in a circular motion. This keeps you throwing in the proper form. This is known as the follow through and is very important.
Once your accuracy improves you can always discontinue holding up your left arm to aim at your target. And after a while of gaining experience and practice you can start using other techniques to put more power behind your throws. But it is crucial to get the muscle memory into your throwing technique no matter what.