If I break down vertical jumping to the absolute basics, jump height is affected by only 3 factors.
1.How much power your lower body (mostly) can express (strenght). This can be enhanced by weight training methods.
2.In how much time your body can express its strenght. This can be enhanced by plyometric training methods.
3.How much weight your body have to throw into the air at every jump.
Theoretically you can improve your vertical jump by any of the above 3 methods. This article is about the 3rd one.
If you have more than 10 percent body fat (for males) (for women, it's about 15-20%), you can probably increase your vertical jump by dropping some weight (fat). Here is some good articles about fat loss (and muscle building):
Body fat calculators:
http://www.exrx.net/Calculators/BodyComp.html
http://www.livestrong.com/tools/body-fat-calculator/
Articles:
Metabolic Typing (by Higher Faster Sports)
Fat Burning for Explosive Athletes (by VerticalJumping)
Fat Loss Tips (by Exrx)