I'm no veteran agent or a million-dollar producer (yet) but I have learned a ton by making my own mistakes as well as watching what the great, and not so great, agents in my office do. 

But they don’t run it they contract it out to a management company who makes millions of dollars !

@Jacobo B. that's what happens to the majority of them here as well.Yes, but these are pools of thousands of homes selling for billions or hundreds of millions.

Big loans (millions) seem to always be balloons or ARMs.  

Build a quality, tenant attracting property, build that cash flow, and then go rinse & repeat.

Perhaps most encouraging, at least to me, is that although many of the guests are now operating multi-million dollar Real Estate businesses, many stated right where I am now―not knowing exactly where/how to start, afraid of making mistakes, etc.Although we live in CA, we are looking to partner with my wife’s oldest son, who lives in CO.

Now I know theres a million varriables, But what do you consider a good return on your rental.

Remember there are five million plus here with every kind of neighborhood imaginable minus oceanfront.  

The more people you serve, the more people you will attract.

You must screen and attract good tenants.