The Mistake: You cooked pasta in a small pot and ended up with a pile of gummy noodles.

When food is added to a boiling pot, it immediately lowers the temperature of the water. Add too much food to too little water and the water will stop boiling, which changes the cooking process and makes your spaghetti taste starchy. If you blanch beans or basil in water that isn’t hot enough, they’ll discolor and turn brown, says Mike Sheerin, chef de cuisine at Blackbird, a restaurant in Chicago.

What to Do Next Time: Use lots of water. “You really want the food to swim,” says Richard Simpson, director of education at the Institute of Culinary Education, in New York City. How much water should you use? For a pound of pasta, use at least a five-quart pot, filled with rapidly boiling water.

The Mistake: You sautéed wet greens.

The excess water on leaves in a hot pan creates steam, leaving spinach that’s stewed and mushy rather than bright and tender. In addition, “hot oil will splatter when it’s hit with cold water,” says chef Tamara Murphy. “So you’d better duck.”

What to Do Next Time: To get tender greens, invest in a salad spinner.

For best results, spin the greens, pour out the water, toss, and spin again.

Wait until the pan is very hot before dumping in the greens, says Simpson. They should be sautéed only a minute or two, until they’re just wilted.