Drink about 3-5 liters of water daily, this is going to help you on the long run. Really nothing other than water helps you to purify your blood and improve oxygen content.
The second ingredient for glowing skin is herbs like neem, turmeric, tulsi, aloe vera etc. These herbs will clean your skin; you can either apply these on your skin then wash off or alternatively you can add these in your diet. These purify the skin when applied and cleanses the blood when consumed.
When you can't find the above specified drugs then your ultimate option should be honey; honey has certain properties that make your skin glow in the long run (but be careful, it may whiten your hair if applied on hair accidentally).
Alcohol may be harmful, but a small peg of wine is certainly not; after age of 30 it's mandatory especially for women to drink minimum 5ml of wine per day in order to have a radiant skin (drink high quality wine, not the cheap ones).
Bleaches done by ammonia will make your skin glow, but may cause wrinkles and other side effects. You can go in for non ammoniac oxy or herbal bleach once in a while. This will improve your skin tone and also gives you perfect radiance.
6.Vegetables and Fruits:
Vegetables (especially green) and fruits make your skin clear and glowing. It also prevents heart diseases and obesity. Add more vegetables and fruits in your diet. Certain important vegetables and fruits are lettuce, beans, spinach, mint leaves etc and papaya, tomato, water melon, orange, citrus etc.
Don't confide in cosmetics that claim to make your skin glow forever; because most of them are fake products and some of them make you addictive. Foundations, day creams, night creams are a cycle that will lead us to buy more and more, product after product.
Don't opt for chemical therapies that claim to make your skin glow; instead opt for natural therapies like oil massages, herbal treatments.
At birth, everyone's skin is crystal clear; it's the pollution, dust, chemicals, environment that degrades the radiance of your skin. To get back your baby soft and radiant skin forever follow above techniques and also try to cover all your body parts when going out.