I am always looking for good sources of information, which I might share with our friends who are reading.

For me it's family, friends, and the food.

I believe single family homes will appreciate the best, and when you are young you are ok with doing rent by the room to friends or family to assist with the costs.

Are you both friends and have unique skill sets and are breaking up the duties of investing based on those skills?

I've had qualified renters move into a rental, add their bum friends or family members, and then disappear, leaving me with bad renters who weren't approved and aren't on the lease.The best practice is to screen every adult, approve them, and add them to the lease. 

The challenge was balancing the relationship between landlord/tenant and a personal/friendly relationship.

You rarely will get both (at least not right now in this current market).If you want to explore different opportunities within various areas of the Valley, get a seasoned investor-friendly Realtor who is competent. 

Always introduce yourself as ..John or maybe Reagan is better....Maybe like hi I'm Reagan like the President, your friendly neighborhood realtor....that's how they will remember you and you want them to remember you. 

In my circle of family and friends, I will say that anyone that owns RE especially in CA has over at least several million in networth and they weren't high W2 earners (no surgeons or attorneys, but librarians, accountants, etc) but this takes years 15 to 30+ years..

Buying a property as primary, renting a bedroom or two to friends is a good way to start building your RE portfolio.