I saw this little baby floating around Pinterest for awhile, and saw an XL grey t-shirt on sale at Goodwill for $0.99, so I thought, "Why not?"
I loved it. It was super easy, and I was happy with the results. The only difference I would make is this: She says to cut a diagonal line across the shoulders, but when I did this, the collar stuck up too much. It looked kinda funny. I would keep the shoulders as is, and do all your angling on the bottom.
(click picture to go to her site)
And here's mine...
If you're tall like me, I would recommend getting an XXL for length purposes. You can always take it in more. I got an XL, and since my frame isn't quite as tiny as the other gal's, it fits slightly different. I'm still pleased with it though.