I trace all my patterns onto tracing medium (Soil Separator paper is my personal favorite), then sew it together to see how it looks. You can just cut out your pattern tissue in your correct size and pin it together on the seamline as well. After making any major changes to the tissue pattern, I cut out a muslin. Now, I don't always muslin every pattern, although there are certainly sewists who do. For this project, since I knew I would be putting a lot of work into it, I wanted to get the fit absolutely perfect before I cut into my precious coating.
My first muslin wasn't too bad, particularly since I had already fixed the swayback in the tissue. In the heavier fabric I used for my muslin, it was clear that I needed a little more room in the bust,
As well as some additional ease across my broad back. After a 3/4 inch FBA and a 5/8 inch broad back adjustment, I made a quick bodice only muslin to check the darts and alignment. I also tried out gathers in place of the darts, which didn't work at all, so I'm glad I muslined it first. After finalizing the dart placement, I sewed muslin #3.
And it worked! I'm happy now with the dart placement and the amount of ease in the bodice.
In back, the adjustment there gives me enough ease to move, without being to large. You can see on the sleeveless side, I tried a shoulder dart, but didn't like the way it looked, so I ended up easing the back shoulder (which I had lengthened with my broad back adjustment) into the front. One thing to remember is that even if you don't think you'll need to adjust the sleeve, you need to set them in to make sure that the back of your garment fits well, as the sleeve effects the fit there.
So in the end, I only had to make a few adjustments to this pattern and they were all pretty standard adjustments for me. I did a small FBA, a broad back adjustment and a small swayback adjustment.
My favorite fit resources are:
Fit For Real People by Pati Palmer and Marta Alto - While the styles are dated, you can't beat the fit information.
The Perfect Fit: The Classic Guide to Altering Patterns - This book has great fit methods, but is often a little light on the explanations. I wouldn't use it as my primary fit resource, but I've learned a lot from it about alternate ways to fit a garment. It is particularly helpful in "non-standard" situations.
Fast Fit by Sandra Betzina - This book helps "diagnose" fit problems by focusing on how an ill fitting garment might appear and what the problem is. Her fit solutions are good, although they don't always apply to every situation.
Debbie Cook's FBA tutorials - Debbie taught me how to do an FBA! I cannot recommend her tutorial's highly enough. They are clearly written and easy to follow. She covers how to do and FBA for many different situations, such as on a dolman sleeve or a twist top.
Sigrid's Sewing Tutorials - Sigrid has collected many sewing tutorials from all over the web and collated them into one blog. Very helpful!
I hope this is helpful. Tomorrow I'll chat a little about tailoring. Stick around for that!