How to Measure for A Show Coat

I am looking to buy a show coat for the upcoming show season. Sadly, there's nowhere around here to try on show coats. I looked online at sizing charts. How do I measure accordingly? How do I measure for bust, waist, hips, shoulders, and sleeve length? I'm fairly petite and wear 00-0 jeans and x-small or small shirts in the junior's section, not that that probably helps.

I was lucky that I could try the jacket on first, but Id have a guess that youd get yourself a tape measure and for Bust.. around your back under your arm and over the breast .. Waist, under the breast .. Arms, from shoulder to wrist and just around your hips for that measurement. I don't think you could go to wrong with that. But just incase find out from the company that if its is to big or small that you can change it, most do

Good luck