Yeah, I made a new corset pattern and I am proud of it :-) I made out my own way and it quite worked.
So to the measuring: measure the waist, hips (at the lowest point of the corset), bust (really tightly - for me it was normal bust measurement - 3cm) and the measurement just above the bust (also tightly), where the corset would end.
Then add some more: measure (from waist) where the lowest point of the corset would be - both at the side and at the center. Waist to armpit. How much the front piece would be higher than the rest.
Some of these measurements are just about design, so e.g. for my corset I used 5 cm higher front piece, the lower edge is lower than waist: 10 cm at the sides and 15 cm at the center.
And you can measure where the side seam would be, so the width of the back.
Start with this construction, using the measurements for back, armpit, lowest edge, hips and front piece hightening.
This will be half the corset with back middle at the left and front middle at the right, so don't forget to divide every width measurement by two!
Here's how to draw the pattern in eight easy steps :)
Measure the front piece from the right edge - the back and front pieces toghether must give you the bust measurement.
As the corset will form the figure, I substracted 1.5 cm from each side edge and drew vertical lines there.
In the middle between them I splitted the lower edge and drew nice hip lines from the waist to this point. You really should imagine women's hips there to get the shape right.
Measure the side lowest point and drew the lower edge. Decide where the 'tucks' will be.
(In fact the left tuck on the front pieces was straight like the other one, but this should work as well. It is always easier to fit and sew straight tucks.)
When you distract the waist measurement from the bust measurement, you get a width that you will divide to the tucks. I used slightly more of this for the front piece, and the least for the tucks closer to the center.
Draw about a middle between the bust and waist line at the front piece. Add the same widths for the tuck as at the waist line.
Join the tucks with lower and upper edge.
Prolong the auxiliary front center tuck line above the bust line. For the other front piece tuck, make a parallel line.
Substract the above bust measurement from the bust measurement and you'll got the width of the tucks at the upper edge. At the three front pieces, I only changed left and right piece. Draw the edge.
Join all the tucks.
Draw the final shape. At each sharp corner, draw a nice spline.
And here's the reality after the whole afternoon of fitting :-)
(If you ever used my pattern, please leave a photo of the corset in the comments :-*)