Buying homes at tax foreclosure auctions

[Ru Monsell]

I'm about to start attending my first auctions on tax foreclosed properties the town or the county has assumed here in Maine. Each property is auctioned separately. I'll be looking to bid on modest single family homes in the assessed range of $150 to $400K. Any general tips for me, or pitfalls to avoid? Other than looking at the assessment, sales history, tax maps, and eyeballing the property, what else does "due diligence" involve? Thanks for your insights.
Ru