 Before sending your PCB design out for manufacturing, it's always a good idea to print out a one-to-one scale copy of it on actual paper. Yeah. It takes almost no effort and it gives you a physical preview of your board before committing to copper. It's surprisingly easy to overlook certain details while your design is still stuck on a screen. So place chips and connectors on the paper and make sure all the outlines and pin counts are correct. With a sheet of foam placed beneath the paper, you can even simulate mounting components. Check for any necessary slots or mounting holes and that you don't have two objects trying to occupy the same physical space. That's a good general rule. If your board has them, try using any buttons, knobs or displays. You can patch up any ergonomic oversights now instead of having to wait for a revision too.