In particular I created door textures for the Praxis U side of things. The Vice Chancellor (in charge of the Void Campus) and the three heads of departments each get their names on the door and even their own coloured room. Elsewhere they also have their names on their rooms, whereas the Technical Officers and the Students get generic names for their dorms (3 tech or 6 students to a room). The Quackems get their names on their state room, whereas the other 3 get numbers.
I've also started using 3 prim dual sliding doors for trek style doors which aren't also lift doors. The main factor here is enough wall space on either side of the door for the panels to slide into. By using a 3 prim double sliding door I can customise what's on each panel more easily.
Some doors have icons (and names) on them to tell you whats on the other side. Anything with EXIT on it leads to the outside.
