For context, I'm a financial planner by profession & have gone pretty deep into tax planning.

Are there standard things you do every time (deep cleaning, fresh paint, etc).

You can challenge your assumptions and broaden your world.4) deep immersion in the markets and dynamics of particular neighborhoods

Look and see what AC model they  haveLabel yours with permanent hot pink spray paintConcrete the unit into the ground -slab 5 inches deep and weld to it.Lock up disconnect box so they get electrocuted when they do the steal look on craigs list for the HVAC guy selling them and call him to come to random addressesAim cameras where the truck parks and don't let them know you can record platesMotion lights that make sound, there's some barking onesFence the yard, put a big dog there when it's vacant, thinking Doberman.Put sign up about dog who bites.Do you really know which neighbor did this? 

Be very careful here, just take a breath and relax, you do not want to get involved in a Breach Of Contract with a GC, while your house is available for him to lien........ ask me how I know.

Will it cash flow enough to have breathing room for vacancy and repairs at 20%?

I saw a pattern that the most successful people were more focused just on getting started and going deep on one thing.

Just head down and dig deep.

Some folks have very different lives for a variety of reasons, so they have chosen W2 jobs or otherwise have not plunged deep into real estate. 

There is a 2 car deep attached garage plus extra space for shop or mancave.