You talking hand knitting here? Machine knitting?
For hand knitting, because knitted garments, tend to have much more give in them, there is much less said about fitting. you just have to make sure the basic size is right for your measurements, the sleeves long enough, that sort of thing.
I suppose if you have a very specific fitting issue you could make pattern adjustments, graph paper used to be how I did it - knitting is very straightforward, one square+= one stitch LOL - but it would be hard to judge how much of an alteration you'd need to make until you'd tried, at least by knitting the back panel and seeing how it fitted your shape. And each different yarn would have a different kind of stretch and drape I imagine.
I don't think there is a simple answer to this one, trial and error (which I hate myself and so am sorry to have to ssay it here)
Leila