It takes several individual items to have a fast-growing, vigorous planted tank. See Books below for more great resources.
Lighting is covered below.
CO2 can be supplied by fish, by the decay of organic material, or by direct supplementation. I hope to write a CO2 FAQ page soon, but for now this brief summary will have to do. If you want fast, aggressive plant growth or to grow a plant that requires high light and fast growing conditions, you will need to add CO2 to your tank unless you have a very, very high fish load. I call the remaining sources magic because there are no examples I have seen that have worked reliably and cost-effectively for a wide selection of users. They mostly fall in the category of snake oil.