If your framing an outside wall on new construction, tack the bottom plate down on a line and frame the wall on the floor, check measurement on the di-angle ,it should be the same both ways. when you have it square tack down the top plate and apply plywood. If you have cut all your top and bottom plates to match your inside wall will look after themselves when you brace up your house. That is not to say you don't check for plumb later.