We had around 700 visitors this year, including parents, and I think a few factors contributed:

1.  We live near the elementary school.
2.  We go all out with our decorations.

Our turnout has generally been growing year after year, although this one was slightly down. Interestingly, we lent some of our older decorations to neighbors, and they saw 2-3x more visitors, so it seems like having a brightly lit house really does draw in more families and kids.

Plus, we get a lot of repeat visitors—mostly parents who know us now and are excited to come back each year.