1. Vegetables sometimes are stir-fried and meats sometimes are browned before simmering begins. To avoid a greasy finished product, be sure to drain off all excess fat before adding the simmering liquid.
2. When the liquid is added, you will need to bring the soup or meat mixture to boiling. Then, reduce the heat slightly so the bubbles slowly rise toward the surface, breaking just before they reach the top.
3. Sometimes the wok or skillet will need to be covered to keep all of the liquid and steam inside. Other times, however, the wok or skillet should be uncovered to reduce the mixture's quantity or to thicken the mixture slightly.
4. In some recipes a mixture of flour or cornstarch and liquid is added to the cooking liquid. Make sure you add the flour or cornstarch mixture at the time directed in the recipe. If it's added too soon, the flavorful sauce or gravy will tend to thin after it thickens.