[sweetorange]

You need to focus first on nutrition . If you aren't getting enough nutrients to nurture your breast tissue , all the hard work is worthless.
After nutrition , circulation. Massage is key for people who are less than A size but of course it takes time, more than a year. 
Then hormones, checking out if they are balanced or not . Also, keep an eye n HGH, IGF-1 & HGF.
Noogling should be also another thing to take into consideration since googling expands mammary and fat tissue .

I think it's possible but you need to have clear it won't happen in a day , it takes tons of time.