If a home sells or increases in market values.

Account ClosedBigger pockets provides great resources in their "tools" section, I think there is a document titled "Promissory note"You can also talk to any lawyer or a simple google search would do.More than the note, however, it is important that the two parties (lender and borrower) trust each other and live up to their commitments.  

Preface, not an atourney, but these are pretty simple/generic answers.1.

Keep it simple at first and branch out as you gain more knowledge/confidence.There has been some good advice presented here in becoming a, "bird dog" for other investors.

@Ivan Barratt - what is your plan to increase the cash-on-cash returns?

Rich Dad's Increase Your Fiancial IQ by @Robert T.

Tenants that are one flat tire away from missing rent will not result in quality cash flow, and yet ironically these type of tenants are the kind that tend to rent in the type of neighborhoods that show the highest pro forma cash flow projections on paper ... too bad those cash flows aren't what you will actually get during a downturn, and you spend much of your time chasing down rent as opposed to growing your portfolio ... too bad that the increases in rents and prices will not tend to keep up with inflation in many of these neighborhoods too ...

With anything old, it's bound to be an onion of problems to replace, so unless it is necessary to replace it, I would not touch it.On the other hand, if everyone else in the neighborhood is updated high efficiency, then that's another story and it makes your house somewhat deficient.Not sure how you get from a $2K replacement cost to $6-10K value increase.

Or admit more students, both of which increases revenue. 

I am laser focused on  educating myself about analyzing opportunities to increase knowledge and decrease hesitation that results in missed opportunities.