A friend of mine brought me a cute tee shirt fom Aruba recently. Unfortunately, it was way too small. It sat in my closet for a while until I figured out what to do with it. I didn't want to just give it away to the thrift store, especially since it travelled all the way from Aruba! I finally decided to add some panels to the sides and see if that would help it fit better. I'll show you how I did it. Here is the before picture.
The picture doesn't do it justice. It is a really bright, almost neon coral color. The first thing I did was crochet a panel to go in the sides. I used worsted weight yarn and a size J crochet hook. I made a sort of triangle shape using a half double crochet stitch that came out to be about 16.5 inches long and about 5 inches at the widest part. You can use a piece of lace or another kind of fabric if you like. Just cut your panel to be the length of the shirt.
Then cut the side of the tee shirt, staying as close as possible to the seam. As you can see in the picture, I've already done one side.
Fold the sides of the tee shirt in so you have the raw part hidden on the inside. Press the fold. This will make it easier to sew.
Place the panel inside the shirt where you want it then match up one corner of the cut tee to a corner of the panel. It's ok if your tee shirt doesn't match the exact shape of your panel. You can't see the overlap on the inside anyway. If you plan to do your final sewing with a machine, loosely hand sew the tee shirt to the panel using a contrasting thread. (This is also called basting if you didn't know the sewing term.) If you plan to hand sew, then use a thread that matches your tee shirt.
Here are my basted panels on the shirt. It already looks like I'll be able to breath in it! I love the color contrast too. If you're happy with it, sew it up with your machine if you haven't done that yet and remove your baste stitches.