Matching thread and needle
Step 1: Try the shirt on, and use the chalk to mark a line on the back of the shirt. You'll need really flexible arms or a friend's help for this step! Draw around your bra strap perimeter. The line will help guide you later on with centering the bow, and prevent your straps from being totally visible.
Step 2: Divide the section roughly in thirds.
Step 3: Cut down the lengths of the two lines.
Step 4: Pinch together the fabric in between the two cut lines to make a bow. Make sure you pinch the bow so the middle is centered on the shirt.
Step 5: Sew the bow together at the pinched mark.
Step 6: Pinch the fabric between the neckline and the first bow. Sew it in the middle to create the second bow.
There you have it!