Always measure your actual body, not clothed body to get an accurate reading for sizing. It is advisable to wear a non padded bra to get more accurate bust measurement
Bust - Measure around the fullest part of your bust and across your shoulder blades.
Waist - Keeping the tape measure taut, measure around your natural waist.
Lower Hip - With your legs together, measure approximately 20cm down from your natural waist and measure around the lower part of your bottom.