1. If you're talking about cooking food in general, then get a friend or family member and make a meal together with them. Absorb techniques and ask a lot of questions
2. Choose a simple meal that you want to make, and learn to make it by trial and error.
3. If you are talking about cooking meat, then perhaps get a cooking thermometer. I only use mine when I grill, but it never fails.
Otherwise learn by your mistakes. Overcooked chicken, ok, write down how large a piece it was and how long you cooked it. Then the next time if you're gonna cook an equal size if meat cut down the cooking time.