I only experienced this after my first. Obviously more experienced with my next two.  I avoided soap on my nipples for a few weeks before my due date and once she was born I expressed a bit  to rub over the nipples but I still got cracked and bleeding nipples.  I ended up using a cream which worked for me and it wasn't until after it had almost cleared up that I found out that if you do experience cracked nipples to try a different way of nursing the baby such a lying down feeding them or the 'football hold'.  This way the baby's mouth is attached slightly off the sore (cracked) area of the nipple giving it a chance to heal quicker without constant pressure or rubbing on the same area that happens during each feed.

Very good tip, Izzy. I did the same thing. Also avoid soaps on the nipple area.