While often we really do not know how our marrying ancestors met, it can sometimes be a helpful "brick wall breaking" exercise to think about possible ways they did meet? Were their parents neighbors? Did they meet at church? Did they meet at school? Did someone travel a distance for a temporary job? Was one of them in the military?
Even if you really have "no way of knowing," just thinking about possible scenarios may get the genealogical wheels turning in your head.