Common problems with throws

The single most common fault is that the disc will turn over before hitting the ground. This fault is caused by one or more of the following:

The angle of release is wrong
The disc wobbles too much
Not enough spin, especially with unstable discs or into the wind
Using a circular swing rather than 'straight' at the target
Not enough distance
Not enough accuracy

Solutions

The angle of release is wrong

Usually the edge furthest away from the thrower is too high. If a beginner thinks he's releasing it level it generally has the outer tip up.

A common technique when learning a forehand is to lift one leg and throwing under it. As well as forcing the release to be lower this also tends to keep far edge lower. It can also help get more flick into the throw. This not only works 75% of the time but also gets beginners psyched as hell; not only did they learn a new throw, but, in their mind, they learned a "trick" throw as well.

Stand closer and downwind so that you don't have to throw it harder.

The disc wobbles too much

Keeping the disc flat during the swing. Avoid wind-ups where the disc is not in the horizontal plane. Pull the disc rather than push it onto its flight path. Pulling the disc keeps the flight plate of the disc trailing behind the axis of the motion.

Turning the wrist over during the release

Practice a palm facing up follow through. (Not a recommended technique for advanced throwers because it puts too much sideways force on the finger joints )

The disc does not spin enough

Using a motion similar to flicking a towel

Start with the disc cocked (or 'wound up') as back as it can go.

Check your grip.

Using more wrist rather than arm.

For a forehand throw, focus on the 'catapult' feeling that one gets in the middle finger, pulling the disc forward with the fingers on the inside rim.

Using a circular swing rather than "straight" at the target

Lead the throw with the elbow.

Follow through by pointing throwing hand at the target.

Not enough distance

Don't worry about it if you’re a beginner. Just more practice is required to get those finger muscles strengthened and the flick automatic. Most beginners try to throw the disc rather than flick it. Thus, if they concentrate on proper release angle (arm and disk) and imparting spin on the disc, a flick of the wrist, they tend to get the basics down quickly. Once the basics are there, obtaining distance will soon follow.

Not enough accuracy

Check that the grip is not finger tips only and the swing is not circular, but in line to the target.