The most common reason for not being able to sleep is not feeling sleepy, or having an overactive brain before sleeping. Here are a few things that can help - 1. Avoid caffeine intake 2 hours before sleep. 2. Avoid heavy meals 2 hours before sleep. 3. Read a book till you sleep. 4. Avoid using mobile phones or laptops (the blue light from them disrupt sleep). 5. Form a regular sleep schedule. 6. Eat balanced meals and avoid heavy meals. 7. Drink 2 litres of water daily. 8. Do some mild exercise before sleeping. 9. Avoid mid-day naps. 10. exercise 3 times a week for 30 to 45 mins each time.