On one of my many wanderings around the internet I came across this picture below of a dress from Modcloth. I loved it so much I decided to attempt it as a T shirt using velvet ribbon.
I started out with a basic Tee shape from my measurements but you could also follow this free pattern for a Kimono Tee. All you'd need to do is cut the pattern down the middle to make front and back pieces.
As you can see I started out by marking my seam allowance in chalk. Then I cut up lengths of velvet ribbon and arranged them on the shirt.
Now for the fun part. I pinned one length of ribbon to the fabric at a time and very carefully handsewed it on. You might notice that it is puckering beneath all the handstitching but these really calm down once you give it a really good iron.
Once it's all handsewed on simply sew up the Tee as normal and voila!