So we all know a huge part of dressing well is getting the proper fit. To many, it's #1, above simplification, color coordination, garment quality, you name it. So that begs the question, how can you determine if something is of the proper fit? Well, truth is, there is a lot that goes into it. And though I can go on for days explaining where sleeves should end, pants should break, legs should taper, etc., I won't bog you down with too many details for now. I'll just tell you this: look at the shoulders.
Poorly fitted shoulders have become one of my biggest pet peeves recently. Most shirts, sweaters, jackets, and coats have visible shoulder seams, and people can tell, consciously or subconsciously, when those seams don't lay on the correct parts of your body. By this I mean that the shoulder seams could land on someone's biceps, or perhaps on the middle of their collar bone, instead of their shoulders. Indications of an improper fit.
I shall demonstrate with some pictures:
Here are some proper shoulder fits, where the seam hits right around where the arm and shoulder meet:
And here is an improper one; see how the shoulder seam extends a good 3 inches past where it should?
So if there's one recommendation I have for everyone regarding proper fit, it is to pay attention to the shoulders. It's hard to alter items of clothing if they don't fit well on the shoulders anyway. It generally ends up costing more than it's worth to make alterations there.
So the next time you're out looking for a sweater, shirt, or jacket, keep a close eye on where the shoulder seams hit your body. Make sure they hit where your shoulder connects to your arm, and after THAT is set, focus on the other areas of fit.