It's a sartorial skill every man should have up his sleeve. Trust us, you'll need it one day, when a button busts in the final hours before a big event. But it's easily mastered.
Believe it or not, you need about a foot of thread to sew on a button. Knot one end and thread your needle. Make two stitches in the shape of a cross 1/8th-inch wide.
Holding the button just slightly away from the shirt, stitch up through the fabric and through one button hole. Then through the hole diagonally across from the first.
Bring the needle up and back through the other holes and repeat three to four times.
Wrap the remaining thread around the back of the button, creating a small stem. Push the needle through the stem a few times and then tie the thread off.
Coat buttons need a little slack to fit through thicker plackets. Create space by placing a toothpick over the button while bringing a threaded needle through the fabric, into the button, over the toothpick and back into the fabric. Repeat until secure and remove toothpick.
Pull the button away from the fabric and wrap the thread around the newly formed stem. Push the needle through the stem a few times and knot the thread just below the button.