Shorts and Leggings:
The main parameter during the shorts size selection should be your hip size. To take the hip measurements correctly be sure to stand in front of the mirror and put your feet together — your hip size measurements should be taken using measuring tape at where your hips are the widest.
The main parameter during the top size selection should be your chest size. To learn your chest size wrap the measuring tape around the fullest part of your bust: be sure to keep the measuring tape snug around your chest but do not pull it tight that you are squeezing your chest in order to take the measurements correctly.