The step-by-step things could also be very basic, like "how to get the right shape for an eye", "how to draw a hoof" or "how to draw an arabian (convex profile), a pony (small ears, short head), a warmblood (long face, robust structure) and a draft (roman nose and whatnot)" type of diagram/walkthrough. Also, I was thinking that if you have full colour, a "how to colour chestnut, bay, black, grey, whatnot horses" list/diagram with a "colour this" copyable lineart could be nice. :)
I remember when I was a kid, I used to get so bored with those "how to draw a horse using circles" things because they rarely went into details (ears, eyes, hooves, etc.) and never got to that "what colours to use on a palomino" stage. So if you're doing something like a step-by-step guide, I vote for details rather than just "how to draw a horse". Also, keeping them to just that linework level might help you with the high standards issue. ;)
Hope you'll find your inspiration before the deadline!