Which sizing should I use when making a dress from a pattern?

I'm trying to make a dress using a pattern. The pattern is a Misses type robe-style dress, so exact sizing isn't that important I don't think. However, when I've come to measure myself I'm a 12 in the bust, 14 in the waist and 8 in the hips! I normally wear a size 8 (Australian) ready made clothes, but am a bit confused as to how to proceed with cutting out the pattern pieces here.



As I said, it's a robe style dress, so it wraps around and ties with a sash. So I take it that the most important places to fit are the shoulders and upper body, as the rest can be cinched in using the sash. My shoulders are skinny, so I don't think using a size 12 bodice is such a good idea. Is it possible to cut out say size 10 at the top of the bodice, but then go to a size 12/14 at the bottom of the bodice (the waist)?Which sizing should I use when making a dress from a pattern?
The very best way to figure this out, is to take the pattern piece for the front and lay it up against your body. Remember that you need to take the seam allowance into consideration when doing this measurement. Which size fits best under the arm and across the front? If its a robe - style dress, I wouldn't alter and of the other parts Just get the top to fit the rest will fall into place. Good luck!Which sizing should I use when making a dress from a pattern?
how many pattern pieces does the dress have? just front and back? or top front and back and bottom front and back? is it designed for a woven or a knit fabric? you can blend the lines using a felt tip marker on the pattern pieces from the 12 to the 14 for you waist to the 8 for your hips- having a curved ruler is ideal for this task. keep an eye on the darts during the process...they should stay on the princess lines if done traditionally. if in doubt, i'd make a quick muslin to see how it fits before you cut out your fashion fabric.