Well, our last homemade one sagged and sagged and finally collapsed under the weight of smarties and jellies and whatever it all was - definitely key to get the gingerbread crispy and hard.
Otherwise, my top tips are to ALWAYS DECORATE BEFORE YOU BUILD, as it can otherwise get, well, very tricky to get the sweeties to stick.
If you want 'real' windows, stick sheets of gelatine on the inside of the walls over the window with icing sugar (agree melted sugar is health hazard on many levels). Looks fab with a lit pocket torch inside.
To create winter wonderland, place house on carboard/tray, surround with cotton wool 'snow' for little santas etc to frolic in, possibly arranged around a small 'frozen lake' mirror. Looks great, although your house might end up a bit cotton woolly.