Every town needs some really basic houses.  Here are a couple of little Plasticville kits done up in a really basic way.   Yet even these illustrate some principles you can use.   Yes, they are gaudily painted, illustrating the lack of taste of the residents.  Notice however that the corners are a different color than the walls.  This makes them stand out a little more.  When many people model buldings, they kinda think that the corners are just part of the wall.  WRONG ANSWER!  You should always highlight your corners somehow if possible.  Otherwise your building will look kind of blah. 

Pastel chalks were used extensively towards the bottom of buildings.  At the place where buildings meet the road, you should put some sort of dark swathe of something (chalks work really well for this).  This is because water accumulates here and starts to create mold.  It will make your buildings stand out from your road or sidewalk bed.  In desert climates, you could put a swathe of sandy-colored paint or chalk to simulate dust that has accumulated there over years.  If grunge is your look, always weather the surfaces of your buildings.  A light dry-brushing of a walnut color was given to the walls, door and window exteriors just to make them look old.

#13 and #666 Ghetto Heights

The interior of these was kept fairly simple.  We just used standard-fare plastic dollhouse furniture and model railroad bits.  They were painted just enough to keep with the overall look of the town (crappy), and arranged in a basic pattern to allow some tactical options during minatures battles.

The floor is standard tile-stamped styrene stock, painted "Psycho Ward Green" (Tamiya flat Sky color) and washed with brown ink.

They didn't really take very long to complete.  The biggest part of the job is waiting for the glue to dry on the styrene floor, and putting the base coat of colors on the various parts.   The weathering, which you'd normally think is the more advanced technique, only took a couple of hours.

We generally give our buildings a light coat of Testors Dullcote or similar Flat.   It is important to buy flat that is ABSOLUTELY FLAT, you don't want any shiny, glossy NEW looking DIRT on your new slum, now do you?