There are several I could recommend if you're not currently attending.We share similar goals - I'm looking to primarily develop a portfolio of rentals, and perhaps supplementing this with some flipping. 

Think someone whose goal is to have the tenants pay the mortgage and in 20 years they have a property free and clear with some cash flow to supplement their retirement.You are looking at it from the point of view of a more sophisticated investor who wants to optimize return over time.

With that in mind it still is probably the best analytics and projections tool available, but best to use it as a supplement to other market research vs using as concrete numbers to rely on.76k in revenue isn’t a bad place to start, but it does depend on purchase price and operating expenses.

Cause the going trend nowadays is the masses value concrete surfaces to recreate or park on, rather than to supplement their diet, oxygen, etc off or cool the microenvironment down. 

I have done this several times to my family's advantage in order to supplement our retirement income but instead supplemented our current income.

Not sure how this works in your state but you could have a supplement if the sewer goes above a certain average rate you charge the overage.

I would like to end up with 4-10 doors to supplement my income.Do you have any relatives or friends that have RE experience?  

But if you choose your major wisely, and supplement it with good electives that can enrich your education, then college can not only make you successful financially but also make you a more well-rounded educated person.    

Yep HP (really just exchangers) will need electrical heater strips for supplemental) Enthalpy calculations tell that story but resi HVAC guys rarely know this.

Most of their training is using trusts for estate planning.I belong to an informal CA trust study group/mastermind & I supplement that with what I learn from others such as Ward Hanigan who lives & invests in CA.Be very careful trying to apply other states practices in different states.