Examples of pitfalls include purchasing in an undesirable area, not understanding the market values (vs. list prices), not knowing the rental values (current and market), inheriting bad tenants, buying a lemon, going rogue on renting and management with no contacts / systems / no legal understanding of PA and Municipal landlord-tenant laws, not having trusted resources and contractors in place, using out of state lenders or shaky financing, throwing lipstick on a pig when renovating a house and wondering why it's ARV isn't increasing, tenants are renting, etc.

Engage professionals to inspect major components such as the roof, plumbing (including sewer lines), foundation, drainage, electrical systems, HVAC, chillers, boilers, termites, exterior walls, balconies, stairs, rails, and concrete.

The architect should also be the one making the submissions through the eclipse system.

I agree with Ashish, great pointing out that although creating a property management type system could open up capabilities for Solo 401(k) and SEP IRA contributions, it can be easier said than done.

Duplexes often have shared systems (plumbing, HVAC, etc.), so make sure these are in good condition.Maintenance Costs: Older properties may have charm but could come with higher maintenance expenses.

It's better than what you'll get from most attorneys and what you'll find on the internet.

I am learning a lot from BP on how to set up a property management system to begin learning the proper way to structure a rental property portfolio. 

They will pay $50 to get something off the internet because they do not want to pay pet rent.Ask them for proof of an ESA. 

Some mentees will act as a bloodhound for the mentor, knocking on doors, driving for dollars, scouring the internet, making cold calls, or performing other services that help the mentor find new deals.

But you need to learn all about landlord/tenant laws, how to do basic repairs, know what average labor and material costs are for common projects. learn about payment systems, how to interview property managers, tenants and handyman services, build a team of realtors, contractors, title, hard/private money lenders, inspectors, appraisers and soooo much more.