Stance
The best dart throwing stance is one that's comfortable. To play the game, throwers shouldn't lean toward the board or tense up. Instead, both feet should be planted into the ground with one foot slight in front of the other. This helps balance out the body while the throwing arm moves forward with the release. Throwers shouldn't favor the front foot by placing more or all of their weight onto it, as if throwing while standing on one leg.
Grip
The grip, like the stance, should not cause tension in the body. Avoid squeezing the dart and keep fingers from bunching by spreading out the ones you aren't using. The only amount of pressure needed is that which keeps the dart from slipping away mid-throw. Also, paying close attention to your wrist will help you level out the dart once you grip it, which will help it along its trajectory.
Aim and Throw
A visual line straight from the dart in the hand to the board helps with aiming. In one motion, stabilize the shoulder so it doesn't move during the throw, lift your elbow, and make a quick move backwards toward your own chin or ear lobe. Then move the forearm forward, causing the dart to accelerate. This technique of unlocking the elbow and using backward motion helps with accurate timing of the release.
Release
The dart should travel in a parabolic trajectory, as if there's a hill or upward curve between the dart thrower and the board, rather than a straight line. Novice dart throwers sometimes ignore this bit of technique and use their strength to accelerate the dart straight forward. Though they might find some success, this can cause the dart to wobble all the way to the board and possibly bounce off it.