Please see data below on size guide per design. The formats vary for some because of different supplier but lets just put this data up in each product page until i figure out how to standardise it. We can add a tip. 

Tips in choosing your size:  Please measure your natural waist (around 2 inches above your belly button) and the widest hip.

Fit tips:

If you are on the border between 2 sizes, order the smaller size for a tighter fit, and the larger size for a relaxed fit. 

If your hips and waist correspond to 2 different sizes, order the size that fits your hip measurement.