Warm serving bowls are a nice touch for steamed vegetables and other foods. When steaming your vegetables, invert the serving bowl over the covered steaming pot so it will heat up while the vegetables cook.
When you pour hot coffee into a cold mug, the mug absorbs heat, making the coffee cool down faster. To keep coffee hot longer, preheat the mug by filling it with hot tap water and letting it sit while the coffee brews. When the coffee is ready, pour out the hot water.
Placing a saucepan on a burner set to "low" can sometimes be overkill for keeping some foods warm—delicate sauces may burn; mashed potatoes can get scorched. Want to apply just the gentlest of steady heat? Place a cast-iron skillet over a low flame, and then place the saucepan in the skillet. The extra layer of cast iron will diffuse the heat evenly. Like these? See more quick tips at Cook's Illustrated.