Well, first, you need to set a goal. Do you want people to have big 4-plot houses? Or 1-plot houses?
Myself, I chose 1-plot.
Next, you need to pick a road size, 2 and 4 work well. If you pick 2, a 1-block outline of each plot needs to be made, if you pick 4, its a 2-block outline.
After that, set some rules, like:
"No messing with roads"
"No placing items on roads"
"No deleting roads"
"No building on roads"
Then, you need to set a punishment for them, and then, enforce it! Thats all up to you, though.
Tip: Make a small area in Creative Mode, if you like it, go with it!
