think the details add a lot of realism to the shirt. We are really home and dry now so resist the temptation to rush these:
Pocket - Not too deep! You can put a cut-off comb or pen in it to increase the illusion of depth.
Hook - Place and align carefully! The hook is a loose fit; it's all to easy to break wood out of the hanger by levering or otherwise fiddling with it.
Stitching - Create with what is known as a 'scratch stock'; simple to make and very effective.
Buttons - If you look at shirts, you'll see the buttons are made from a different material, often shiny plastic. I turned from some scrounged horn from a furniture restorer with spigots to fit in the holes I bored a long time ago in the button strip. Alternatively, use another wood or 'artificial ivory'. I guess you could use real buttons... Don't glue the buttons in until you have bleached the shirt, if that's the way you want to finish it.