This is possibly my new favorite dress for my baby girl. It is just so cuddly!
I started by cutting off the sleeves and then along the shoulder seam and side seams. 
I also loosely measured how long across it was. I semi used this measurement but adjusted as I went on. 
I pinned approximately how long I needed. 
I used the front piece as a template for cutting the back. 
I overlapped the neck pieces by about 2.5 inches and pinned them and trimmed them since they angled a bit. 
I used the sleeve from the t-shirt for the sleeve and measured width from the onsie. 
I drew with washable marker and make sure the opening would fit a baby hand. Of course I made it about a half inch larger than I thought I needed for the seam allowance. 
I cut both sleeves. And trimmed the edges. 
I put right sides together starting from the middle and pinned. Then sewed them together using a zig-zag stitch. 
After sewing both sleeves I turned it inside out matching front to back and adjusted it as needed. 
Of course my original pattern needed some tweaking.

















 




































