Pin along the sides to make the desired width of your shirt. I recommend doing a basting stitch at this point so you can try on the shirt and make sure you got the right fit.
The sewing machine I used for this project is the Singer Fashion Mate – it’s a fantastic machine for beginner sewers since it’s not too complicated, but it also leaves a TON of room to grow as you develop your sewing skills!
Once you feel comfortable with the new seams, sew them down with a sturdier stitch. I recommend a zigzag cross stitch to prevent fraying.
Trim off the excess fabric.