My mental white board is a source of constant amusement for my writing partner, Lindsay. When I am playing connect the character dots or trying to add a new thread, she will often chuckle and tell me to flip the board back a week or two to see what I've missed. As irritating as her suggestion is, it is surprisingly accurate! I simply shuffle whiteboards . . . toss one to the back while bringing another forward. I have one for each of my characters, each of my manuscripts, as well as for those works I am critiquing. I don't know how I keep them all straight --probably heavy doses of caffeine and an insane need to compartmentalize!
She asked me a few days back what my character map for our MC, Jake, actually looked like. It took some time, but I think I've created a rather accurate rendering for her to view. Here it is! It may not make any sense to you; but to me, it contains all the information I need to create a fully fleshed-out character.