Look for untrimmed  bushes when the the neighbors have clean yard... look for semi damaged roofs and houses that have mold/mildew on gutters and siding.  

Keeping their homes & yards like this may have something to do with it Once you've dealt with enough tenants from hell you stop asking those questions though. lol, it's what they do.

Hello, I moved to Arizona, and was looking to see if anyone has a recommendation of a person or company to do some basic, fairly small scale yard maintenance.

Nothing wrong typical 3bd 2 bath single garage and big back yard.

For example, adding washers and dryers, fencing in the yard and accepting pets for a fee or possibly adding a carport or deck for perspective tenants?

I was Extremely nervous to get started, but I convinced myself to rip that first sheet of siding off in the back yard, and once I got started there was no turning back. 

I build elevators in NY/NJ and while NYC is busy with all the high rises going up in Hudson yards, NJ is also very busy with apartment complexes.

I do front yards on new construction with sprinklers for 3k per house.so it could be to get to 600k you need to dump 100k into it  @JD Martin  and then with holding costs and sales cost your 405k offer is probably what the BP calculator said it needed.. but something is off here.. seems to me based on pictures that house if its really worth 550k should have sold aright at that. but maybe the ARV as I stated is way off.. 

I rent in B areas , one of the reasons they rent well is the tenants want a yard 

who takes care of the yards?