I rarely wear a jacket - just to interviews - but the ones I have fit kind of like a blazer I'd buy from American Eagle or Gap comfort wise. They aren't too tight or boxy but kind of fitted if that makes any sense.
Fit the shoulders first - shoulder seams should be in the right place. Other areas can be altered reasonably easily, but shoulders aren't simple to alter.
If there's a seam down the back, this can be adjusted too. You don't want it to look "baggy" or too loose in the back.
Go with a single-breasted style and as low a "stance" as looks good. Stacy and Clinton generally say if you have a big chest you want the stance to be higher. You should be able to wear it buttoned comfortably.
The waist should also be snug. Look for curved seaming or darts to avoid anything that looks boxy.
Make sure the sleeves are the right length - well past the wrist - most people wear their sleeves too short. But 3/4 or bracelet sleeves are also fine if you like the look.
I rarely wear a jacket - just to interviews - but the ones I have fit kind of like a blazer I'd buy from American Eagle or Gap comfort wise. They aren't too tight or boxy but kind of fitted if that makes any sense.
I always feel like they're boxy on me and tight in the armholes. I think I'm with you on the wearing jackets only to interviews. AE is a good idea for casual ones. I'll have to check them out. Thanks.
I agree that making sure they fit well across the shoulders and chest is easiest/best, and then altering from there.
Recently I have found some jackets that are kind of sweatery or knit, but are dressy enough for my place of business, and they are more comfortable than a regular jacket.
I have this one and like it
Or maybe something like this kind of styling:
I have bought a few from TJ Maxx and recently one from Macy's on clearance.
If you are curvy at all, you likely will need to have the jacket fitted. Most jackets will not fit all that well just off the rack. They're also one of the priciest things to have tailored, but worth it IMO. I have big shoulders and am a C cup and always have to fit for my upper body and then have the waist taken in.
__________________
"Good taste shouldn't have to cost anything extra." - Mickey Drexler