I’m working on a game to teach basic electronics. It’s hard to come up with electronics puzzles instead of homework problems. I found these articles to be useful in understanding puzzles:
http://www.scottkim.com/thinkinggames/GDC00/bates.html — The art of puzzle design lies in creating an original set of problems and solutions that are appropriate to the story you are telling. Even so, puzzles fall into recognizable categories and it is important to know what they are and when you can use them. Here are some of the categories.
http://www.gamasutra.com/view/feature/5901/evaluating_game_mechanics_for_depth.php?print=1 — Former Insomniac designer Mike Stout takes shares a useful rubric for judging the depth of play mechanics, including checks for redundant ones, in this in-depth design article, which contains examples from the Ratchet & Clank series.
http://www.rockpapershotgun.com/2013/09/20/untold-riches-an-analysis-of-portals-expressive-level-design/ — Hamish Todd’s writes, “Portal has the best-designed first-person puzzles I’ve ever seen. They’re surprising, focused, and concise. They are also designed very perceptively, and we can learn a lot from looking at this perceptiveness. Read on for an analysis of Portal’s level design, and some lessons about what learning from it can do to improve game design.”