One of the most frustrating things in shopping for clothing is to pick out several items, take them to the dressing run and proceed to find they 'DO NOT FIT'.

Now I take my notebook with my measurements, a tape measure and I measure the item first before it ever goes into the dressing room with me.  The best part is I find that I do not have to be a slave to the size tag anymore.  Every manufacture has their own set of sizes, so you can flucturate between several sizes. So take those measurements and you tape and shop away happily.