- Acquire a seam ripper, a needle, black thread, and a thimble.
- With a seam ripper, detach the collar (the part that folds down on a normal shirt).
- Sew up the seam that's left; it now looks like a band/mandarin collar.
- Sew a small button onto the outside of the very back of the neck.
- Sew a small button onto the inside of the front of the neck, right behind where the top button already is.
- Voila. No studs, buttonholes, ironing, or sewing machine needed.
PS: You will have to adjust the size of the collars you wear; nobody that sells clothes at the mall intends for anything to be as tight as the clergywear people do. So, on a typical 'small' size shirt, try a size 15.5 collar. It takes some experimentation.