1. Avoid mobile and tv screen viewing after 7 pm.
2. Avoid coffee, sweets or any carbonated or non carbonated beverages.
3. Have dinner before 8 pm, and eat light, easy to digest food but do not over eat.
4. Have a small walk before bed time.
5. Have at least 10-20 mins of quite time where you can relax before going to bed.
6. Read an interesting book if you like.
7. Do not work or do any activity on the bed except sex on your bed. So that the association of sleep with bed is clear in your mind.
Next Steps
If the above do not work kindly meet a good clinical psychologist and follow what he says.