The other method, maybe a but simpler, is to tie a normal shoe lace knot, except loop round twice instead of once as the second last movement, if this makes sense.
Do your knots lie across the shoe or toe to ankle when tensioned? The former is more secure if they are normally like the latter then swap the way you finish the knot. Hard to explain when you've had a beer sorry but I saw it on QI and since then have not had any problems with my TNF hedgehog noodle laces that were always coming undone otherwise.
