I've looked quite a bit for resources demonstrating how to fake spot varnishes and print finition in general (embossing, foil, flocking, etc.) on real mockups (i.e. no Photoshop). I would exclude binding from this since it's a huge topic by itself.
I did find some videos for hand embossing on YouTube, mostly from the scrapbooking crowd but it works and I also found a method for foiling which required a laminator. I would prefer something low-budget that students can apply easily. To my surprise, I couldn't find anything much about faking spot varnishes except hearing of using nail polish before as well as this Yahoo Answer which sounds messy and more appropriate for a big surface:
rubber cement masking and then apply a shot of clear spray paint, and remove the rubber cement mask.
What are your preffered affordable methods for faking finition on mockups for clients?