Print your nyan cat head. Size it to how big you'd like your charm to be.
Cut the pixelized head, and then cut elements such as its mouth, eyes and cheek blush.
Trace/pin images on felt, and then cut them up. I cut up two of each element cause I wanted the head to be double sided.
Glue/sew the elements on. Be mindful on where you stick the elements, you want it to resemble the original image. Line the two sides together and then sew the sides up or glue them and cover them with felt. I sewn the sides up, but then I suck at it so I'm thinking of doing the other method next time. :)
Don't forget to add a loop for your phone strap attachment and stuff your plushie charm before you close it up. And there you have it :)