Like many described above, a private lender can be anyone from a friend or family member or otherwise a company not affiliated with a conventional lender aka a bank.The qualities you seek in a lender are subjective to the investor, but overall they should be able to close your loan in the time-frame promised from the start, communication is of paramount importance as well.

Pay attention to the very first communication you receive from a potential tenant.  

Looking forward to communicating with you all!

I would at communicate with him before threatening to kick his butt out...  

No problem with communication, etc.

Get a mentor to help you and always Check with an attorney to assure you are in total compliance.I build new for rental primarily for the following reason: 1) I am a builder and have the KSAO's (knowledge, Skills, Abilities, and Other) means necessary to efficiently and effectively build; 2) I buy all my land substantially below market value (usually off-market); 3) any land I buy at market has an immediate value-add component that can quickly make it worth more that what I paid for it; and 4) Cap Ex is generally MUCH less for new construction which means a stronger cash flow up front, but you are always going to need to maintain a suitable Cap Ex account if you are truly going to hold for more than I'd say 7-10 years.... but everybody has their separate opinions and thought process concerning what the "right" amount to designate to Cap Ex is proper..... 

The other advantage is the technology and ease of communication/distribution.

Its very important to maintain constant communication with the short sale bank for any Auction dates on their files.  

On an apt, I do these same things and increase the NOI of the property thru increased rents, revenue adding and expense saving efficiency improvements.  

I do believe the communication is not as it should be as I'm being told one thing then questioned about the same points later.