take a piece of origami paper, any color you want :)

fold a triangle..

fold 2 triangles pointing to the middle :p

now it should look like this ;)

now fold a...

triangle! :)

:)

GLUE! :)

yeah! we're almost there..

and fold back :)

there's an opening at the upper leg of your small triangle... put your fingers there and fold a square, it should look like this.

it's a little envelope :o

cut a heart, this is optional ;) but still cute :3

voilà, you're finished!