So following on from my thread
here in the Fly Tying section here is my very first step by step - a guide to crochet flies..
Tie in two different coloured threads/yarn/wool (one at either side of the hook shank) right up to the butt.

Loop the green thread over the hook shank and under the red thread.

Push the crochet needle through the loop on the right and under the hook shank, take hold of the red thread and pull back through the loop.

Pull the thread straight through and tighten, pulling on both threads.

Make another loop with the red thread but this time under the hook shank and over the green thread.

Push the crochet needle through the loop on the right and over the hook shank, take hold of the green thread and pull back through the loop.

Again, pull the thread straight through and tighten both ends.

Repeat this process to where you want to tie the threads off.
A short video can be found
here.
I did make another
video - with commentary.. but it didn't really turn out the way I intended. (Neil was holding the camera on top of my head pointing down at the vice.. we are still laughing now!) Fly tying can be fun.
Anyway, Hope this helps... and the video makes you laugh.
Debbie..