How old is baby? How often are you nursing? Are you supplementing? What makes you think you haven't got milk? Keep nursing on demand, it will stimulate milk production. I can help you better with more information.
I agree with the other suggestions, but i was also advised to pump some too, even if you dont keep it, the more you nurse or pump the more milk you make. Your body works as supply and demand, the more you feed the more you make. Also keep taking your vitamins and drink plenty of milk.