These four measurements are the basics for blouses, jumpers, and dresses. If you want to make sure of a better fit, take the other (non-numbered) measurements also.
1. Total Chest Measurement
Put the measuring tape around your chest right under your armpits and straight across your chest above the bust.
2. Total Bust Measurement
Again bring the tape across your back and under your armpits, but in front bring it around the fullness part of the bust.
3. Waist Measurement
Straight around your waist.
4. Hip Measurement
Measure the circumference of your hips at 9" below the waist or the fullest part.