I have a nice cotton summer shirt that I really like, but it had several problems. For some reason the people that design clothes for larger women think we have shoulders like linebackers and arms as long as a gorilla does.
Here's what I did to correct the too wide shoulder without taking the sleeves out. I made a tuck or a pleat at the shoulder seam that brought it up just enough (collar to the left, sleeve to the right). This shirt happens to have a decorative seam there but it works well even if it does not.
Another problem is that the fabric was cut on the bias on just one of the edges where the buttons go and the upper part was always wrinkly and would not lay straight.
This is the inside of the shirt, collar is to the right, I cut a slit through just the inside layer of fabric on each side and inserted a piece of a wide zip tie cut to size. Just like a collar stay. No one but me see the inside so I just did a quick & messy hand-stitching to seal the slits up. I also hand-stitched the front edges down as it is easy to put on over my head, this now keeps it from gaping in between the buttons as the fabric is fairly lightweight.
And here it is with home made neckline stays and no more twisted & wrinkled fabric. It works very well, is not too stiff while wearing and best of all I no longer have to iron it!
So 3 problems fixed with minimal time and effort.