The length is usually taken from the shoulder seam to the hem and is very important if you have a distinct preference, for example if you like a little more length for extra coverage in the rear.
When buying pants and skirt, the hip measurement is usually the most important measurement. Normally taken from about an inch above the base of the fly across the width of the garment, it will give you an idea of the fit as well as a more accurate size measurement than the waist. With seasons fashions changing so regularly as well, you may also need a 'rise' measurement. This is taken from the point where the seams all meet in the crotch to the front of the waistband and will give you an idea of how high, or low, a pair of jeans or pants will sit on the torso.
To measure yourself:
Bust: Keep your arms at your side and place the tape measure around the fullest part of your chest, under your arms. Make sure that the tape measure remains parallel to the floor.
Waist: While standing, wrap the tape measure around your natural waistline and keep the tape comfortably loose.
Hips: While standing with your feet together, wrap the tape measure around the fullest part of your body between your waist and your knees. This is approximately 20cm below your waist. Make sure that the tape measure remains parallel to the floor.
Of course, if you have a 'problem area' then that is going to be your most important measurement and is the one that you should ensure the best fit for.
Or measure a favourite item.
Lets say that you are looking to buy a new dress for that party coming up next month. Take a dress from your wardrobe that fits you as you want it to and lay it down on a flat surface. Measure the arm pit to arm pit and then double it; that gives you the bust measurement.
Now, go to the narrowest part of the body section and measure straight across, and then double that number; that is the waist measurement. Do the same at the widest part of the body (hips) and then measure from the seam where the shoulder meets the sleeve (if there is one) to the hem, and that gives you the length (don't double that one).
Measurements regularly used include;
Bust - taken underarm to underarm.
Hip measurement on a skirt or pants - this is usually just up from the the base of the 'fly'. On a dress or skirt, it is usually the widest part of the body section where it flares out from the waist.
Length - taken from the shoulder seam to the hem.
The rise - that is the height, for example on a pair of jeans, from the crutch to the waistband. That will tell you how low on the hips or waist that the pants will sit.There can be a front or back rise. If it is not stated then you can assume it is the front rise measurement given.
Upper arm measurement - Sleeves are made in all shapes and sizes so a sleeve width measurement may be important if you are slightly outside the 'norm' - whatever that may be.
Bottom hem width - this is especially important when buying flared or A-line items. It will give you and idea of exactly how much 'flare' there is.
Upper thigh width- tells you how tight or loose a pair of pants or shorts will fit.
Inside leg length / outside leg length - will give you an idea of the length of a pair of pants and whether they need to be altered.
Sleeve length - it is best to get a measurement taken from the inside seam that usually runs on the underside of the sleeve, as that will give you the most accurate measurement.
and remember, check that the measurements are in centimetres, not inches, especially if purchasing from overseas.
It also pays to know a little bit about fabrics.
Most fabrics these days are a blend. Anything that has lycra or elastane in the fabric has stretch to some degree. Polyester can be stretch or not, depending on the style. Some 100% cottons also have some stretch.
If you would like some stretch in the fabric and it is not stated in the listing, always ask!
100% linen has no stretch or give at all and garments that are bias cut also rarely have any stretch. Items made from 100% linen or cut on the bias usually fit better if you get the next size up from your usual size.