There's a saying in the wood working world, "Measure Twice, Cut Once." This saying also works in the sewing world.

To pick out the correct size pattern, you must have accurate body measurements to know what size pattern to buy. This is extremely important because each pattern company sizes their patterns differently.

For women, the three most important measurements are the  bust, waist and hips. For men, you will need neck size, chest, and arm length. Thes measurements will give you the basics for selecting the right size pattern.

 Bring your measurements with you when you go to   buy your pattern. Compare your measurements to those found on the back of the pattern envelope. Then look to see what size you should select according to that pattern company. Each pattern company sizes their patterns differently, so it very important to do this with every pattern you buy.

 Patterns today come in multiple sizes. So, if you    wear a different size on top from what you wear on the bottom, you only need to buy one pattern.

 For example, if you want to make a jacket and pants  outfit, but you're a size 10 on top and 12 on bottom you only have to buy the one pattern. Each pattern piece has cutting lines for sizes 10, 12, 14, etc. Then you cut the pattern according to your size.