Use either a thread that matches your felt or use a contrasting thread such as purple or white to give a little more oomph to your stitching. Then starting in the middle stitch a flower shape. This is easy because essentially poinsettias have leaf shaped petals. Just stitch from the middle and make one side of the leaf (an ellipse), when you get to the tip, stop with the needle down, lift your foot and flip your square around and make the other side of the lift. Once back to the center, lift your foot, flip your square around and start on your second petal. I usually make 7 petals and don't worry at all about getting them even. Real flowers do not have even petals and yours don't have to either.
So leave a comment with a link if you try these. You could make them any color if you wanted a flower that was less holiday oriented. I'd love to see how yours turn out! Any questions? Let me know.