In addition to what Bill E. said, I try to get a good idea of what expenses could come up soon.  

One additional benefit, I have had luck contacting them after a year or 2 and asking if they'd like to settle the note for a discount.

In addition to cash in cash returns and capital gains at sale, I also look at the debt coverage ratio to see if the property can support its debt service in these scenarios.  

My wife plans to partner with me over time and at some point I might look at taking on additional partners. 

I've gotten 3 quotes for an approx 400 sq foot master suite addition (plans already approved by the city) and the least expensive was $150,000 - tile, fixtures, etc not included.  

I wrote a blog post last night that may help prompt some additional questions for you to use in your search.https://www.biggerpockets.com/blogs/8756/51616-tru...

Occasionally, you will find private money lenders that require a percentage of profit on the sale, rather than, or in addition to, the other fees and/or interest.Loan terms can also vary, but most private money loans tend to be about 6 months.

For me it makes sense to contribute to my 401k, realize the tax savings and simplify my life (by not managing additional assets in real estate).  

I think Eric Lee at Proline Tax Advisors does it: http://www.prolinetaxadvisors.com/The legal filing with the state is essentially the same no matter who you use.

I am considering using this property and some additional equity as leverage to buy a larger multifamily, but haven't yet found a property that I'm interested in.My goal is not to have a ton of properties, but to have cash flow to exceed my expenses and leverage reduces cash flow.