Tips on measuring.
Measure over your under garments
Hold the measuring tape level and firm, not tight.
Measure under your arms and over your bust. It’s easy if you get someone to do this for you, make sure you hold you arms out.
Measure your natural waistline, where your clothes already sit
Measure approx 20cm down from your waistline, and don’t forgot to measure the fullest part of your hips