We always do mockups in muslin or some fabric we have on hand, where will just throw the piece in rental. We (or more specifically one of my employees) also does a lot of draping in muslin… which we transfer to paper. Such as this dress:
I mainly deal with period wear, but anything by Mueller:
Fundamentals Menswear › M.Mueller & Sohn
2 books I’ve used for mens period wear are The Blue Book and The Red Book. The Blue Book is an earlier system where the coats use a “dropped shoulder”, where the Red Book is a newer updated system with a modern shoulder. Both these (as well as tons of other pattern making books) are available as free downloads from archive.org.
Frederick T. Croonborg Blue Book of Men’s Tailoring: Grand Edition of Supreme System For Producing Men’s Garments (1907)
https://archive.org/details/grandeditionofsu00croo
New supreme system for production of men’s garments
https://archive.org/details/newsupremesystem00croo
There’s a book - from the FIT in NY I think - we have on adjusting commercial patterns to fit. I also have an old tailors book that has a section on fitting & adjusting suit patterns… things like adjusting for shoulder slope and posture. I doubt the book in print, and I can’t recall the name, but I can check.
And not just measure… over 40+ years I’ve made a lot of dumb mistakes, fortunately very few disasters. Always check to make sure you have “flipped” your pattern pieces the correct way or you may end up with all one side of a garment. Also check the nap… when ever I’m not sure I always layout piece in the same direction as if there was a nap. If you’re cutting multiple layers with different fabrics, make sure you mark the fabric with the narrowest width to place on top… nothing worse than marking out the widest, and you find out layers underneath are not wide enough to fit the pieces near the selvage. Even when layering from a single roll the fabric width can change - especially with wools - like happened with the recent movie job we did over the summer. I made sure to keep pieces at least an inch away from the selvage on the marked layer in case the width varied - which it did!
I did another job over the summer remaking a set of 2 chair covers… I took the pattern off an existing one. The fabric for the new covers was a cheetah print sort of weave and cost like $500 per yard!! Besides having to deal with a very complex puzzle of how to layout the pieces., which I literally spent like 2 days figuring out… with the yardage I had you can bet I probably measured a dozen times before cutting anything.