I recommend buying breast pads before you even give birth and taking them to hospital with you. Milk production intensifies greatly few days after birth. Hyperlactation causes milk to leak from breasts not only during breastfeeding but also in between feedings. Breast pads protect underwear from getting dirty. You just unglue the adhesive strip and place the pad in your bra. Remember to change pads regularly (every 2-3 hours). The moisture filling the pads can cause skin irritation and inflammation. Don't re-use disposable pads.
Overabundant milk supply develops a couple of days after birth. You can try to reduce the amount of milk by expressing some of it with a breast pump. However, don't express too much milk as it could stimulate the breasts to produce even more. In order to ease the pain, take a warm shower before feeding and cool your breasts with moist muslin squares cooled in a fridge (don't do this before feeding as it could hinder the milk flow). Press the cool compress to breasts for no longer than 2-3 minutes. I also recommend cooling breasts with cold and ground cabbage leaves. The smell might not be great but the method is really effective.