Another suggestion is not to do it. My friend regrets it now, because she did it earlier, using the method of embedding thread, and now it seems a bit rustic. Of course, which method to use depends on your eyelids.

I am single, but it's wrinkled, so it's a fake pair. I just stick it completely, using double eyelid glue. It is said that Joseph Cheng's double eyelids are glued out, so don't cut them off, and occasionally they may even go in.