Firstly, start off with a sweatshirt.
I cut mine off the shoulder a long time ago, so that's completely optional.

See the paint splatters? When I was helping backstage when I was Glinda in the Wizard of Oz in high school, I got splattered with green paint. I don't want people to see that!
So, let's cover it with a bow, shall we?!

Let me teach you how to make a bow.
First, take a square of fabric and fold it in half.
Sew along the marked edge.

Fold it like you would a paper fan.

Tada, a bow. Now, make the little tie around the middle, and it's good to sew.

I made a pun.

Choose where you want the bows.
I chose two on the bottom and one off center near the neckline.

Sew the bows in 5 places, the outermost corners of the bow, and then a slip stitch right in the very middle, to ensure that it stays exactly how you want it.

There you are!
A sweatshirt adorned with bows.