For instance, in looking for myself, there were 50 William Van Winkles. This list gets cut drastically after adding search criteria on my home state or even home city. But it's also possible to go too far. By giving the people finder too much information, you may just cut right past the person you want. Start broad and work your way in.
Some people finders allow for wildcards or partial names.
Most people finders don't recognize case, so don't worry about capitalizing. Also, some finders allow you to sort by affiliation. Switchboard's advanced search listed a ton of interesting groups, such as the YWCA and Greenpeace. Four11's organization search is doubtless the most extensive, covering anything from military outfit to high school. All are worth trying out.