I made Lilly this Ninja mask for our video THE NINJA'S. It was easy peasy and used up a leftover t-shirt that I had used to make Lilly a pair of SHORTS.
This first picture is the left over shirt. I made the eye mask on that top part and over the sleeves. But If you were using a whole t-shirt you could do it from neck hole to hem.
Next, I drew an eye mask shape like so, making sure to make a curve in the middle for the nose. P.S. the eye holes need to be closer together than mine shows.