With characters, there is a variant of the mind-map called a coterie chart. You may wish to consider it.
First, make a diagram of all the characters. Then, link them with arrows. On the arrows, write one emotion. The main problem with this is that the emotions between characters tend to be dynamic over the course of a story. However, the coterie chart gives you a good idea of who hates who and why. If you like to start big, I'd recommend "Nine Princes in Amber" by Rodger Zelanzy as an excellent starting point. It involves the plotting of a royal family, nine brothers and four sisters, to decide who will be the next king of Amber, the One True City.
