Hello.
Following tips will help you certainly:
1. strict sun protection. Regular use of sunscreen is mandatory. use good sunscreen with UVA n UVB protection daily two-three times a day.
2. diet rich in
vitamin A n Vitamin C: citrus fruits like amla, lemon; walnut; almonds, papaya etc will help
3. use dermatologically tested cleansers and other cosmetic products
4. consult a dermatologist for skin tone improvment and consider treatment like chemical peels