I started out with this shirt. Since men's button down dress shirts are most common, this is what I mentioned in my title. However, the shirt I used is actually a women's dress shirt. I found it at the thrift store for only $1. I loved the colors and bought it to see what I could make of it.
The first thing I did was cut off the sleeves and the collar. The picture of doing this is pictured below. Next, I cut the dress into the shape of a dress by making it smaller at the top and wider on the bottom. After that I flipped the two layers right side in and sewed both sides.
Turn the dress right side out and flip the edges on the top inward. Be sure the edges are wide enough to fit a piece of elastic through. Sew the edges, but leaves about a one inch gap to thread the elastic through. After the elastic is through, you can sew it shut.
You can now cut out the straps using your sleeves. Measure out your child so you know how long to make them.
Sew them on the inside of the dress and tada!!! Your dress is done. If you want, you can add a flower to spice it up. Make your own design with the leftover fabric.
So pretty and unique!