Each time I sew up a new bodice or jacket I always dread the fitting issues in my upper torso. You'd think that once you've learned a fitting technique that it would basically apply to all, right? Not so! While I don't always sew up a muslin, I always fit the tissue pattern to my mannequin, this gives a sign of how much it's going to take to tweak the pattern in order to get the fit. I'll have you know that I am fitting obsessed and require certain points that are my pet peeves to look just right. One of my main problems is "gaposis" anywhere on the bodice top, whether it be the armhole, neck or upper chest. Sometimes I 'swivel my seams' and other times I 'pivot and slide' but mostly I just add more length and width over the bust and ease it to the back which so far does not require any adjustment. This book is very helpful as is the "Fit for Real People". I like this book because it shows the best approach for each design. I hope that I've conveyed by now that one adjustment has yet to fit all for me.
I've also successfully broken some "rules", like smashing parts of the patterns paper so it's flat and folding little darts here and there, so far, so good. If you are having any fitting issues, don't give up, if you keep at it- you'll find the tricks that will be just right for your body.