There's really no need to prepare your breasts for breastfeeding. In the old days women were advised to rub lanolin on their nipples, or use toothbrushes/dish scourers to "toughen them up", but there's no need for it.
What would help immensely would be to prepare yourself mentally, like read up as much info as you can about breastfeeding. Arm yourself with information because breastfeeding is something that needs to be learnt and practiced with your baby before you get the hang of it. It took me around 3 months till I got it right and felt comfortable that I could do it.
Read up on breastfeeding myths, that cleared a lot of the old wives tales and other things that people told me.
All the best for your breastfeeding journey! It definitely is enjoyable once you get the hang of it