Just beat the Blood-starved Beast (should be done by end of 2015 at this rate) but not really sure where to go now. Wandered around for a bit but don't really see any other paths.
Beating the BSB gives you the first Chalice so you can start exploring the Chalice Dungeons. Chalice Dungeons can be crafted in the Hunter's Dream, they are optional content but you can find nice stuff and quite a challenge in there.
To continue the main storyline you should go back to the cathedral and search a way to explore the upper city of Yharnam.