Those that like a relaxed life and keep it cozy and small but highly efficient and profitable and then those that go big and make money off of scale.

The same techniques work for multifamily as for SFR: https://www.biggerpockets.com/blogs/8814-investing-with-rei-kitI also wrote a post on how to evaluate a residential multifamily that goes quite in-depth and might be useful right now: https://www.biggerpockets.com/blogs/8814/73755-18-essential-metrics-to-a-complete-real-estate-investment-analysis Best of luck!

It is very much necessary that you know properly about that area and is any tax relaxation is available to that property or not.

@Moises Rosario just for the record, bandit signs are "illegal" in most places, but they are still a great marketing technique and, even if you are fined, it's normally small. 

I've read about some type of "snowball" technique that involves using the cash flow to pay off the mortgage quickly, and then buying another house, etc. 

At some point, these prices will not keep rising but relax if not fall a bit.

That is a technique that I have heard of being used before -- I am not sure of its viability. 

I'm familiar with getting leads from direct mail and other advertising techniques, but I figured buying leads/deals could be easiest.

I think you should relax.  

Great to hear and if dirty carpet from showings is your biggest problem - relax be happy ;)