Food sticks when the pan is not hot enough, the food is wet, or you try to move it before it releases on its own. Preheat an empty stainless pan over medium-high for 2 to 3 minutes. Cast iron needs longer, often 8 to 10 minutes, because of its mass. Then add 1 to 2 teaspoons of oil, pat the food dry, and leave it until it lifts without a fight.
Proteins bond to hot metal as they cook. In a properly hot pan, the surface sets and browns fast, and once that crust firms up the bonds let go. In a lukewarm pan, the surface never sets quickly enough, so the food sits there gluing itself down. Moisture makes it worse. Water on the food turns to steam on contact and pulls heat out of the pan, which is how you get gray, stuck meat instead of a sear.
Flick a few drops of water into the empty pan. When they skitter as tight beads instead of pooling and slowly sizzling, the surface is well above boiling and ready. If you have an infrared thermometer, 375°F to 425°F suits most proteins. Add the oil only after that preheat, and swirl it into a thin film. It should shimmer within 20 to 30 seconds. That shimmer is your cue to put the food in. Cold oil in a cold pan soaks into the food instead of forming a barrier.
A 10-inch pan usually needs 1 to 2 teaspoons of oil for a single steak or chicken thigh. Use an oil with a smoke point above 400°F for a hard sear: refined avocado, grapeseed, or a plain vegetable oil. Whole butter and extra-virgin olive oil strain at that heat.
Once the food is in, press gently, do not pull. A chicken thigh in a hot pan will stick for the first 3 to 5 minutes. That is normal. If a nudge with the spatula meets resistance, give it another 60 to 90 seconds. When the crust is ready, the food shifts on its own or slides with almost no effort. The same rule holds for steak, fish, and tofu. Eggs and delicate fish want medium heat, not a hard sear, but they still need a fully preheated pan.
Sound is useful while you cook. A steady sizzle means the pan is holding temperature. A sizzle that fades often means too much cold food went in at once. A violent, spitting crackle means the fat is too hot or a lot of moisture just hit it. Adjust the burner, do not just wait.
The preheat, the water test, and the release cue are in Why Food Sticks to the Pan. More technique notes at Chefitt.