The pitfalls are obviously bad neighborhoods (easy to gauge talking to brokers or running crime maps) and also find the right property manager depending on the size and class of the property. 

These items are important so that you can budget accordingly and price the deal correctly.What size properties are you focusing on?

Each is about the size of a large plastic container or shopping cart, and they mount right to the wall.

The brands I've been bid on have been:Eco WindowsCGI Sparta SeriesLawson IndustriesESWindowsAssuraAssura is from home depot, main advantage i've found is that they have a quick lead time of 4 weeks, compared to everyone else saying 6-8 weeks.CGI I heard its a reputable brand with a good warranty Lawson, cheapest quote but Im' hearing has a huge lead time now and they have been messing up peoples orders with sizes or specificationsES Windows, comes from Colombia and I heard spare parts, replacements and customer service is terribleEco, I haven't really heard much about but price seems close to what I'm being quoted for CGI Spartas Anybody on here with more experience that can help me narrow it down? 

Yes, for every data-based analysis in real estate, you need a large enough statistical sample size.

@Jason Rowlett If you are in city limits, I would call 311, and ask about building codes and minimum housing size.

Depending on the size of your portfolio, I suggest considering either "PROPERTYWARE" or "INNAGO":Propertyware is ideal for larger portfolios, offering customizable and automated reporting features.Innago has been very effective for me, enabling property marketing, conducting screenings, and managing rent and maintenance requests.

Maybe put some of that into a money market account or the stock market, so if an HVAC does go out in 2 months you can pull out $4-8k to replace it (depending on size, location, etc). 

@JayHinrichs, you are correct that there are above 8000 members in Subto and with that some sort of dilutive nature based on the sheer size and interactions.

The easiest way to increase your bottom line with a residential rental property in any city of minimum size is rent it out fully furnished.