This is a perfect trasnformation for an old t-shirt to give it new life. It works best on crew necks because the neckline ends up larger than how it began but don't let that stop you starting with a tshirt with a larger neckline!
Fabric scraps also work well, mixing patterns gives this t-shirt it's special look.
Find an old t-shirt that you don't mind cutting up a little, maybe one you haven't worn in a while.
Measure the new neckline along the front (purple line).
Cut off the collar as close to the collar as possible
Create your pattern by taking half the neckline measurement and drawing a curve that matches the curve of the neckline, when you get to one end, make the curve more curvy (or decrease the radius of the curve's centre). At the end that will be on the shoulder, give it a straight edge.
Add seam allowances to your pattern on all sides and cut out 4 pieces. flip 2 pieces so that they are right sides together and sew all the way around the sides and bottom curve, flip right sides out and you have your collar.
Sew the collar to the t-shirt, right sides together and then fold over the rough neckline (front and back of t-shirt) and sew a topstich all the way around.
Collar done! For variations, try a pointed collar or make a collar that goes all the way around by cutting 4 pattern pieces on the fold of the fabric hence making pieces twice as large!
Also, to get the ribbon effect at the bottom of the top, mark out and make a series of button holes (an even number) along the bottom an then thread some scrap fabric or ribbon though them.
Attach a pin or broach to the front of the top for extra girliness!