It is one of the few locations where singles with possibly the same beliefs and interests as yours regularly gather.
Essentially, all you have to do is show up, become involved, and get to know people.
Most churches have sports teams, music programs, or mission trips that offer great ways to meet new people.
Find somewhere to serve short-term so that you can get exposure to people.
However, you limit your opportunity to meet singles if you take such a narrow approach.