Summarize:

Before contemplating surgery consider everything you can do to make your breasts appear bigger. Learn how selected exercises can slightly increase your bust size. Know what will have little or no effect on your breast size:  Potions, supplements and creams are all snake oil. Your breast size is controlled by genetics and the pituitary gland in your brain. Products that sound too good to be true, are to good to be true. Bulgarian beer has no effect on the size of your breasts, either. Chicken or other foods have no effect on your breast size. Drinking lots of water is good for you, but will not change the size of your breasts. Your sleeping position has no effect. Whether you wear a bra or not has no effect. Rubbing or squeezing your breasts will not change their size. Breasts do not get bigger with sex, or a lack thereof. Pumps and machines will not increase the size of your breasts. Breast size is partially controlled by estrogen. When taking the birth control pill some women will get larger breasts, while others will not. Such a change cannot be counted on and is considered a side-effect.  Pregnancy increases bust size for the duration of the pregnancy and nursing period. Afterwards they go back to their normal size and sometimes get smaller than they were before. Breasts contain fat cells, so gaining weight will increase their size, unfortunately it will also increase your overall size. There is no known way to use weight gain to only increase the size of your breasts.
Contemplate non-surgical measures. Research exercises. Understand the limitations of commercial products.