Here's a panel quilt I did. It is designed as a wall hanging so it is small. I added an inner boarder and fussy cut pictures from coordinating fabric and framed them attic window style.

You could use a narrow border that has not been pieced around the panel first to frame it. Then add a pieced border for more focal interest. Then just keep adding plain borders. The pieced borders could be as simple as 4 or 9 patches or a log cabin or something more complicated like a star block. Have fun!!!

You have gotten lots of help here and the rest of us have benefited from the answers to your question. I like the examples shown in the pictures-all of them.