The process of UV mapping (the way i do it)

Basicly from the images below, i have tried to keep the same kind of materials together and objects, so these are the buildings, steps brick work. The glass is on their as well not sure if different materials make a difference but yeah.
I started by scaling the smaller building, then using some maths and a ruler on the screen i worked out the proportions for the other objects, once again i dont know if scaling effects the quality of the textures (stretching) but this will be looked at more next week.
I used planar mapping mainly by grabbing faces that were facing the same direction on the building and projecting them i did a test to see if overlapping effected the objects in maya and so far it seems that it doesnt effect it, so all is good so far. Automatic mapping was used for the house detail and that seems to work quite well too.
All the stone objects now need to be textured and they are sorted. (I hope)
I do know that texture artists do use the whole UV area but i dont know how they get everything to sit perfectly yet, more research is needed.