I often look through magazines and try and find someone who I think may look like what a future DC of mine and my OH would look like, then I try and figure out what name would suit them... 
OR
I have a name or two I like in my head, and then I spend the day 'trying them out' on strangers in the street/work etc to see what type of person/look the name seems to 'fit'.
I know my RL friends would think I'm raving mad, wondering whether any MNer's equally obsessed interested in names has done this or similar?!!