Vegetables are to be stir-fried need to be cut so that as much of their surface area as possible is exposed to heat: that way they cook faster. The larger root vegetables should be cut into thin batons or sliced diagonally. Broccoli and cauliflower are best separated into small florets with the remaining thick stems sliced diagonally. Leafy vegetables should be finely shredded.
The most efficient order in which to add vegetables to the oil is: roots first, then florets, sliced pods, and beansprouts and leafy vegetables last, allowing a minute between each addition.
Add any liquid such as soy sauce with the leaf vegetables, then cover the wok to allow the vegetables to steam slightly.
** Asian Recipes