I make backing 1/4" larger all around. Sew backing only together on each piece, then sash the front. You have to design with that in mind.
Another method uses the backing cut much larger, and folded over to bind each block then joining the blocks. (Commercially available patterns) I didn't like that one - I kept burning my fingers pressing it.
The commercially available one has templates you can buy. 2 different sized squares. The larger square for the backing, smaller square for batting and block.
I've also used sashing on both sides. You zigzag blocks together. I always had a problem lining up. The back stitching was never centered.