Efficient Researching, Pre-Foreclosure

I have not looked in a while for properties and wanted to hone in my research technique. Does anyone have any suggestions so that I am not wasting my time in my efforts. I do not have the cash to buy at the steps, but rather to get the home current and purchase directly from the home owners. Here are my current research steps:

Foreclosure Research Steps:
1) Does the property have equity? Minimum of $150,000 (zillow.com)
2) Is preliminary title clean? cr.ocgov.com
3) Have they gone through the foreclosure process multiple times, or years? cr.ocgov.com
4) Did they file for Bankruptcy? pacer.org
5) Find Phone Numbers.
6) Knock on Door.

Are there any other research steps that i should do to remove all the unwanted properties from my knock on door list.