Specific weight training exercises can help increase your vertical jump. A combination of specific modes of training will be most successful.
The musculature of the quadriceps, gluteus maximus, and hamstrings are responsible for extending both the knee and hip joints. These muscle groups greatly contribute to jumping due to their ability to create considerable force production through the joints.
Power is the product of strength x speed, or work performed over time. Resistance training can develop increased strength and sprint training can help develop speed.
Plyometric training provides a link between training for speed and strength.
Plyometrics is an explosive-reactive system of drills that include repeated hops, bounds, and jumps. Agility and running are prime examples of activities involving the stretch shortening cycle.
The basis of plyometrics is the training of the strength-shortening cycle. Plyometric training has a very high neurological component as well as a significant musculoskeletal aspect. As such, it should be implemented on a periodized, planned, and individualized basis by a strength and conditioning professional with considerable training and experience in the field.
Vertical Jump training, and the application of the quick, classical lifts known as the olympic lifts can also be utilized to improve jumping ability.
Again, it's important to emphasize the concept of a planned, specific approach to training. Train hard, but train smart.