Make sure that you are drinking enough water.Make sure that your food has more colours on its plate especially get some leafy vegetables, some oranges into your diet. Reduce the consumption of salty food, especially like chips and fast food.They have high quantity of salts which are going to dehydrate your body and it's definitely not helping your skin either. Don't forget to exfoliate your skin regularly.Lastly but not least, always remember to remove your makeup before you go to bed. This makes the whole way in improving the quality of your skin.
Also read this :-How do I care for my skin at home without going to the beauty parlour or dermatologist?