Take your actual body measurements as they are more accurate than measuring over your clothes.
Height
no shoes, feet together flat on the floor, measure from the top of the head to the ground.
Neck
measure around the base of the neck where the collar touches the skin.
Chest
measure under the arms at the fullest part around the chest.
Waist
measure around the natural waistline.
Hips
measure at the fullest part around the bottom.