I have been listening to Bigger Pockets religiously for about a year.  

One thing that's made a huge difference for me - tracking your follow-up touches religiously.

For maximum income, just like putting up religious photos/symbols, or family photos, you don't want to turn guests off. 

In an interesting video on Youtube, a lady is interviewed saying that she's raising money to buy apartment buildings for all cash (no mortgage) because of her religious beliefs. 

I am invested in their fund and they pay their solid return religiously.

One thing I'd add: track your activity religiously, not just outcomes.

Now I use the 70% rule religiously and walk away from anything that doesn't hit my numbers upfront.

Subject to can work if you track the original loan payments religiously and have a backup plan if the seller gets cold feet.

First off, the "Best" strategy is to: 1) Ensure your Rental Agreement spells out what Tenant is responsible for, and what LL is responsible for; 2) Ensure at signing that Tenants understand their duties and responsibilities; 3) Religiously perform Annual Inspections to document, with photos, overall conditions, and seek out signs of any leaks (water is your enemy!)

(religious book store next to a adult book store, not good!)