There is something special about food cooked in a wok called wok hai? What is it and how do I get my food to have it?
Wok Hei is the "essense" imparted by the wok when stir-frying over very high heat. The characteristic flavor is due to the the Maillard reactions and the charring of the ingredients.
Practically speaking, most home stoves do not have sufficient BTU output to achieve Wok Hei. If you have a gas stove with sufficient output, consider yourself fortunate. Get the wok really hot before adding the oil and ingredients... and stir vigorously. You should also make sure to crank up your hood fan/ventilation, since there will be quite a bit of smoke generated.
For those without a high BTU stove (myself included), a suggestion was made here regarding a burner that could be hooked up to a propane tank.
Wok hai (or hay) is literally "the breath of the wok". It is used to describe a stirfry that is cooked over high heat with no ingredient being over-cooked. It is devolped by cooking over a lot of BTU's and paying close attention to your timing and ingredients in the pan and geting your food into somebody's mouth before it has a chance to cool.