Please keep in mind that Brooklyn is a large area (73 square miles) and most of my repertoire of neighborhood tours are in the north and western segments of the borough (with the exception of Coney Island/Brighton Beach, Dyker Heights, Victorian Flatbush, Sunset Park, and Borough Park). That said, I've gone all over the borough for private tours and am always happy to explore further.
Below is a map from Wikimedia. From the north, see Greenpoint and then Williamsburg, and below the Brooklyn-Queens Expressway Fort Greene and Clinton Hill. From Prospect Park, Park Slope is just to the west, and follow Flatbush Avenue northwest to the edge of Fort Greene and then Downtown Brooklyn. Go west from Downtown Brooklyn to Brooklyn Heights, and north to Fulton Ferry.
Some Brooklyn books:
about Brooklyn food/restaurants ("the coolest city on the planet"), and Josh Ozersky's curmudgeonly response
tracks Brooklyn real estate and neighborhood issues; Brooklyn Based
offers a "guide to Brooklyn life." Brokelyn
knows that Brooklyn need not always be expensive.