primitive stitchery

I am an artist. I have come up with a line of stitchery designs. I now need to include instructions. I was wondering if anyone would be so kind as to post a link or describe the best and most logical way to write instructions for a stitchery pattern. I have purchased some, but they are all different and I'm more confused than when I began as to the best way to word mine. All designs are just outline pictures on tea-dyed muslin. Any help or advice much appreciated!