Equipment

Below are a few peieces of equipment that will help you get better results.

Thera Bands
The one weakness they have is that they have a maximum tension. Meaning even the strongest band can only provide so much resistance while free weights can keep increasing as you get stronger. This should only really affect the more elite athletes. For the rest they should provide more then enough resistance. As they are much cheaper and more convenient at home then free weights I suggest getting them. Your local sports store should have some or a similar product.

Thera-band.com

Jump Rope
Using a heavier rope is beneficial. Do not use one that is light and made of light fabric. You will not be able to make it move quick enough to maintain a good pace. Make sure the rope is almost twice your height with the handles. On the right are a couple of examples of good jump ropes.

Jump Rope 1

Jump Rope 2

Exercise Balls
Exercise Balls are great for advanced versions of exercises. They make exercises more difficult by creating an unbalanced surface that you have to balance on using more of your muscles.

Bosu Balls
Bosu Balls are like half exercise balls. They give much the same benefits as exercise balls but allow for a different range of exercises to be done on it (ie. Push ups).
It is called the Home Balance Trainer on their web site on the right.

Bosu.com