French knots don't have to be done on cross stitch aida fabric, you can do them on anything! For this example though, I will be using aida.
STEP 1: Decide where you want the first knot to be, then bring the thread from the back to the front. I have used a full piece of embroidery thread, so the photo's are a bit clearer, but for this size aida it is a bit big. I'd normally use 2 or 3 strands, not the full 6.
STEP 2: Wrap the thread around the needle. I know this seems strange, but this is how it's done!
Step 3: Wrap it round again. I like to wrap it round twice, but you can experiment with how many times you wrap it, it'll give a different size/style knot.
STEP 4: Remember last weeks Half Cross Stitch tutorial? I mentioned how the aida is made up of lots of woven threads. Now we've wrapped round the needle twice, we insert the needle slightly under the hole that we came up in. There are 4 strands of weave below the hole, I go through after the first strand. The closer the better really, but you cant use the same spot/hole you came up in.