Transforming a shirt or blouse into a dress is a simple task even if you have minimal sewing skills.
Select a blouse or shirt. It can be long-sleeved, short-sleeved or sleeveless. You may want to choose a top that you really like except for the way the bottom half fits.
Choose a fabric that coordinates with the blouse or shirt. If the top is patterned, choose a solid fabric, or one with a simple design. If the top is plain, choose a fabric of any pattern that you like that matches it.
Cut the shirt horizontally, just under the chest. Turn it inside out. If you are using a blouse, keep it buttoned and pin the front in place before you cut it.
Measure the fabric around your body. It should be one and a half times your circumference. After cutting your fabric to the correct width, you will also want to cut it to the correct length. To find the length, measure your body from below the chest, where the shirt will end, to the length where you want the dress to end.
Make a tube out of the fabric, sewing the raw edges together. Ruffle the bottom half of the dress by making a basting stitch all the way around the top and pulling the thread lightly. Make sure you leave enough space to get it on and off your body.
Pin the bottom half of the dress to the shirt top, being careful to keep the ruffles in place. The shirt and the fabric tube should be inside out. Adjust your ruffles as needed to make sure that they are even all the way around.
When you are satisfied that your dress is pinned in place, you can sew it all the way around. You can sew it by hand at this point, making small careful stitches in two rows, or with a machine. Turn your dress right side out.