If you're shopping for a dress with patterns, make sure the patterns are in proportion with your body.
For example, if you are petite, go for smaller patterns, along with smaller jewelry, smaller shoe buckles and straps. Do the opposite if you are taller or have a bigger structure. Go for larger patterns, chunkier jewelry and bigger shoe buckles and straps.
Same thing goes for men. If you're a guy with a smaller build, consider wearing shirts with smaller, narrower collars than wider ones. If you have a bigger build, then you'll look better in larger, wider collars.
Remember it's all about the fit and proportion.