Good golly, it is time for another helpful hint to the male population at large. It is time to step up your Formal Style. Today the hint is namely how to fit a collared dress shirt. The Situations that call for you to use the helpful hints mentioned today are frequent and very important, namely Weddings, Church Services, Formal Dinners, Job Interviews, a Nice Afternoon in the Park, Hanging Around the House, basically any situation that could call for you to look like a tad better version of yourself.
First and foremost! Get a collared shirt that actually fits around the neck. To see if the collar fits, slide two fingers in between your neck and shirt. If you can fit three fingers, it is too large. If only one, it might be uncomfortable, especially after a wash.
Next, Sleeve length. The cuff of the shirt should fall comfortably at the wrist bone, then raise your arms out straight in front of you, if the shirt raises more than half an inch up your arm. then the shirt is too short in the arms. Also, the seams where the sleeves connect to the body should sit right on the edge of your shoulder. Not up on your shoulder or hanging off into the air. But snug.
There are three standard torso fits, The French, The American, and The English Cut. If you have an athletic build, The french cut, would probably be the best choice for you. If you are a much bigger man, then the American cut would probably be your best bet, and The English cut for something in between.
A dress shirt can look good while your doing just about anything. Good luck with the tips, I hope it helps you step up your style.
Anyway, that's just a quick reference! Here's a few more references, that cover what I said, but far more in depth.
HERE, for more info on collars.
HERE, for more info on Sleeve Length and fit