Leads, leads, where are the leads.

[Scott Bell]

This is the second time I'm trying to start a serious investment. I have bought two homes but both were personal homes that converted to rentals when I moved. I put very little serious thought into the investment aspect at the time. Now looking to the future I need to ensure I make money when I buy, not hoping I can make some when I sell. 

So I ask what are a few of the ways people find leads. I know the common ones Wholesale, MLS, and agents. What are some of the uncommon ones.