If you don’t know heat, then you’re missing a lot about cooking. Use all your senses to sense heat. Touch is obvious, but don’t forget that you can also smell, hear, and see heat.
The aroma of heat is unmistakable. Nose up to a heating dry skillet and you will know what I’m talking about. With very high heat on a greatly seasoned wok, the Chinese master chefs call it the dragon’s breath. During the cooking process, your nose will tell you how well it’s progressing. Of course, there’s the dreaded burn smell. Although, after years of cooking you will find that there are many variations of the burn smell. And that there are good burn smells that years of practice can only achieve.
The sounds of heat will tell you if your cooking is flourishing. It will tell you how vigorous or how weak your heat is. Remember, heat is your friend, and the stronger it is, and the better control you have of it, the tastier your food becomes. Learn the subtleties of the boiling and the bubbling sounds of your cookware to know where you are in terms of cooking temperature.
Visual cues are just as important. I’d sometimes put on my contacts for a big cooking session because I just hate it when my eyeglasses fog up. Learn how to gauge the doneness of your food by sight alone, not by bites or having to slice open your food. A simple examination and maybe a feel with your fingers will give you enough information. The crisping around the edges, the way the food moves around the skillet, etc. are enough heat clues for your chaotic cook.