1. It's important to have all of the ingredients ready to go before you begin stir-frying. You'll find that once you start, cooking goes too quickly for you to prepare ingredients between cooking steps. Start by slicing all of the ingredients, combining the sauce ingredients, and cooking the rice or pasta called for in the recipe. Arrange all of the ingredients in dishes near the wok so you can reach them easily when it's time to use them.
2. When everything is ready, add the cooking oil to a wok or large skillet. Lift and tilt the wok to evenly distribute the oil over the bottom. Preheat the wok over medium-high heat about 1 minute. To test the hotness of the oil, add a single piece of vegetable to the hot wok. If it sizzles, proceed with cooking the seasonings, vegetables, and meats as directed in the recipe. You may need to add additional oil during stir-frying to prevent the food from sticking. The amount of oil needed for stir-frying depends on the wok's surface. For example, a wok with a nonstick surface probably will need less oil than a wok with a steel surface. If you need to add more cooking oil, add a small amount at a time, and bring the oil to frying temperature before proceeding.
3. Seasonings, such as minced garlic and grated gingerroot, generally are stir-fried first for 15 seconds so the distinctive flavor of the ingredient seasons the oil. Just stir the seasoning into the hot oil, keeping it in constant motion. Because the amount you will be stir-frying at one time is so small, it's important to keep the seasoning moving the entire time so it does not burn.
4. Now you're ready to stir-fry the vegetables. Begin by stir-frying the vegetables that take the longest to cook, then follow with those that cook more quickly. Use a long-handled spatula or wooden spoon to gently lift and turn the pieces of food with a folding motion, as shown below. This ensures that the food will cook evenly. To prevent scorching, remember to keep the food moving at all times. Remove the vegetables from the wok after stir-frying.
5. Stir-fry the meat, poultry, or fish. Since overloading the wok or skillet with food will slow cooking, stir-fry no more than 12 ounces of meat at one time. This means that for most recipes, you'll begin by stir-frying only half of the meat until it is done, and then remove it from the wok. Then, you'll stir-fry the remaining half of the meat. Return all of the cooked meat to the wok.
6. To thicken the sauce, push the cooked meat from the center of the wok. If the sauce ingredients you've already mixed together contain cornstarch, you'll need to restir. Then, pour the sauce mixture into the center of the wok and cook, stirring constantly, until it thickens and bubbles over the entire surface, as shown below.
7. The final step of stir-frying is to return all of the stir-fried ingredients to the center of the wok. Stir everything together to coat with the sauce. Then, cook and stir the mixture as directed in the recipe until heated through. To assure that your stir-fry is piping hot, serve immediately.