Best improvements for class C properties

[Ian Cosley]

Hello there BP, 

I have a 4-plex  ( 4 x 2bd / 1ba units ... shared laundry ) that I would rate somewhere around class C. The property is built around 1980 , and to the best of my knowledge have never been upgraded.  The area is kind of run down and I can't see it improving but I still see rents raising at other rentals in the vicinity.  I recently had a tenant move out and have the opportunity to improve a unit.  

In your opinion, where should I focus my efforts in regards to improvements on this unit (or the overall building?) for the best ROI ?