|Carpentry for Vocational Schools - A Teachers Handbook|
The more braces that are fixed to the wall frame the more rigid it becomes. Braces must go from bottom plate to top plate at as low an angle as possible. Before braces are fixed to the frame you must check that the frame is square. This is best done by measuring the diagonals while the frame is lying horizontal on a flat surface.
If the frame is squared and braced before it is erected, you can be sure the external corners are plumb.