What's great about this is that most of the hard work has already been done!
1. Find a dress that fits your little one. You will use this as your stencil for the outline of the dress.
2. Place this dress on top of the shirt - lining up the collar/neck line. Using tailor's chalk draw the outline of the dress on the shirt. Be sure to make it wide enough around the waist, bottom and skirt. Mine could have done with being a bit wider as the orange dress is made in a much stretchier fabric. I realised too late!
3. Being sure to add a seam allowance, cut out the shape of the dress in the shirt. I'm going to use a french seam which will require twice the amount of usual seam allowance for your side seams (not the arm holes).
4. Pin and stitch the side seams of the dress.
I've used a french seam here. This is neater and feels smoother against the skin! To do this line up the seams wrong sides together. Pin and stitch both side seams. Trim excess seam allowance. This feels counter-intuitive as initially your raw seam is on the outside of your dress. Now turn inside out and press. Pin the seams again and stitch using the same seam allowance. The seam will now be on the inside of your dress and is a very neat finish.
5. Pin and stitch bias binding around the arm holes. To ensure a neat finish allow for a little overlap and be sure to fold and press the ends of the binding before pinning in place.
I've made my own binding but your local haberdashery should have a good selection, including pretty patterned binding.
6. Pin and stitch bias binding around the bottom hem of the dress. This really neatens it up and looks very sweet if it matches the binding used for the arm holes.
I didn't get the chance yet but I think that changing the buttons over to these will make this dress extra sweet!