I looooove to sew - absolutely dreaded to HAND sew because I always had trouble with where my knot would end up.
My fellow sewers feel me. I'd try to tie off my thread by looping it around the very end of the length, on my fingertips, pushing that little knot down tight as near to the end of my thread as I could get. And woe-was-me if I was sewing with a single strand and had to try to tie a double knot. Getting that second knot to lie right on the first was always a struggle. UGH!
So, here's an Instructable about a trick that saved my sanity and opened up a new world (I could have never started to do Hawaiian quilting, which is all handsewn, without it) of enjoyment.
Step 1: Step 1
Hold an end of the thread between your index finger and the needle, near the sharp end.
Step 4: Step 4
And so! You have a knot perfectly placed at the end of your thread and your hands aren't all cramped up, or anything. Easy-peasy!