Most Helpful Guys
It means you are pretty and look like someone who could have easily been a friend, someone who is both attractive and not egotistical, someone with whom we would feel comfortable. The girl next door look means you are a much better candidate for a real relationship than the drop dead gorgeous girl we saw at the mall.
Most Helpful Girls
I think it means someone who doesn't wear a lot of makeup or fancy clothes, it's someone who is just naturally pretty without standing out too much in a crowd.