This will vary with markets but kitchen, bathroom, and landscaping (curb appeal) have the highest returns.

As far as my goals, I would love to help an investor up that curb appeal while adding some investing tools to my toolbelt.  

If approved by JP, constable will serve the Eviction Notice, and  if they still don't move out, JP will order a forcible eviction in which constable will show up at house, and "keep the peace" while you and your workers remove the people belongings to the curb.

Landscaping will make the most difference in curb appeal.

Both are Single Family Homes located in a well curbed community with public schools & universities around.

Both are Single Family Homes located in a well curbed community with public schools & universities around.

I have a SFH that I purchased for 50K put around 6K of cosmetic rehab into it (paint & carpet was really all the interior needed did some landscaping myself for curb appeal) got the down payment of 10K from my 401K.

Privacy, sound barrier, and curb appeal all improved tenfold within those two days.

I've also met with a developer who said he looks to "double" on every deal  - meaning he is spending 200k for land/permits/materials/labor and targets a 400K sales priceIn my area, 4 units+ is the trigger point for all sorts of additional complicated planning reviews and requirements, curbs/gutters, traffic studies, environmental reviews, etc...       

I polish and repaint, pay attention to curb appeal and all those things that bring in great tenants.