I wish I could claim ownership of this very clever idea.  The Invisible Belt by isABelt is just what my pants needed!  If you've ever wanted to wear a 'statement' belt over your pants--and couldn't, because they wouldn't stay up--this nearly invisible belt is exactly what you want.  If your pants are too big or, the waist gaps, you must wear a belt that goes through the loops of your pants.  Doing that doesn't allow you to wear a fashion belt, too.  But now you can.

The belt itself is made of plastic.  It's relatively thin, lays flatly, and the buckle is nearly as unobtrusive.  It's important that you follow the directions (included with the belt) to adjust it to the correct length.  Remember, it's made from plastic, not leather, so treat it gently.  To help the buckle stay in place, position it just under your pants' front button.  It shouldn't move if you do that.  The isABelt won't be seen and your pants will stay up.

Now you're free to wear a blouse or sweater over your pants, completing your look with a fashionable belt. Clever, huh?