Tater is a skinny boy. And Hubby likes to buy him shirts at coaching conventions. So this is what I have to do to them.
Cut off sleeves
Lay shirt that fits on top with sleeves folded under. Cut off excess side fabric, leaving 1/2″ for seams
Cut seam allowance off sleeves
Open sleeves and pin to opened out shirt, sew with zig-zag or serge
Sew underarm and side seam all in one
Fold up hem, leaving a wide hem to let out as he gets taller (but probably not wider)