French knots are considered to be a nightmare for most embroiders, but I love them. They're very delicate and cute and they never look the same.
Their size can also vary greatly, so you can use them in a ton of ways. (Check the first photo - the top row is French knots made with six strands of floss wrapped once, the second row the knots are wrapped twice!) You can use them for the center of flowers, as eyes, for polka dots, and even as lines if you're feeling patient. :D I use them most often while dotting i's in text.
To pull off a french knot successfully, you'll need to follow these steps:
You'll knot these on the back as normal. For the cleanest work (if you're not making loads of them!), tie off between each french knot. Otherwise, you'll have tails everywhere if the knots are spread out!