It really depend on the model. If you use just one plane, then you can't use refraction. Some times you can get away with just a simple face glass - saves you some rendering time.
But if your model require proper "thick" glass with refraction you need to model a solid glass sheet.
A glass material will have 100% transparent diffuse layer. Then a Fresnel layer with IOR at around 1.5 (there are lists of IOR values you can look up). Then of course the refraction layer if you have "thick" glass.
VfSU 1.05 comes with glass materials. If you right click in the VfSU material editor and choose import it will normally point to the materials that comes with VfSU. Look at that.
Normally the default settings are fine for glass. Though, the Refract Color in the fresnel map is by default black - I prefer to turn this up a little, just to ensure you always see a hint of glass reflection.
There really isn't any 100% exact settings - most things with rendering will depend on your scene.