There's no need for your glue-ups to be frantic and desperate; that's what leads to open joints and out-of-square assemblies. Simply follow these basic steps before you glue up and your cases will be square. First, make sure all the components are sized correctly and all surfaces are flat. Then, make sure you have the proper clamping blocks and cauls, sized and configured to direct and distribute clamp pressure where you need it. Now, do a complete dry-fit before you glue. Something wrong? Learn how to correct it. Follow the tips in this Fundamentals, and your glue-ups will be less stressful, your joinery more professional.

From Fine Woodworking #226