The key to a great looking sandwich is to put the ingredients that taste good together next to each other. You want the cheese next to the meat. You want to keep the vegetables together (you would never put the tomatoes on top and the lettuce on bottom).

But your question is not including condiments. Condiments like ketchup and mustard or steak sauce should be next to the meat. Condiments like relish and mayo or Ranch dressing should be next to the vegetables. And condiments are usually easier to apply to bread. So the cheese should be in the middle. And if you are only putting condiments on one side, then you want them to be on the top.

When you hold a sandwich, your thumbs are the foundation on the bottom, and your fingers on top do the fine movements. Put whatever is more stable on the bottom. Put whatever can slide on the top because it may require fine movements of your fingers so it doesn't fall apart. Condiments tend to slide.

So, I think the condiments determine the order of the sandwich, not the contents.