My First Book of Knots by Berndt Sundsten and Jan Jager contains the following little ditty to remember how to tie a basic knot called the bowline.
'A field mouse comes out of its hole, runs around the tree, and then goes back into its hole.'
There's a bit of information on the fisherman's knot as well.
'It's said that sailors used to send a thin string or silk ribbon with this knot to their girlfriends to see if they were still in love with and loyal to them. If the knot came back properly set, everything was as it should be. If not, then things were over.'