how to increase property value?

[Paul Gallardo]

very recently bought a upper/lower multifamily for 93k with an FHA loan. this place was built in the 1900s but have been decently taken care of. New roof withing 3 years, new insulation throughout last year, new cabinets 2014. new carpet ect. Most alarming concern is an old furnace. In case it would go out it is covered in a home warranty paid for buy seller for first year. Link to pics added. the empty unit is the upper unit (bottom unit is ocupied)

 for the most part pretty plain. the upper kitchen space is not well utilized. Light fixtures through out are outdated. What part of the house should i focus more time and money in? what renovation really bring up appraised value? i am trying to refi after renovations

https://www.realtor.com/realestateandhomes-detail/413-Elmore-St_Green-Bay_WI_54303_M74991-66238#photo0