A professor of mine just forwarded me this paper which was the best review I've seen on N=1 experimentation (Mirza et al. 2017): http://jameslindlibrary.org/wp-data/uploads/2017/02/J-R-Soc-Med-2017-08-Mirza-330-340.pdf
In particular, I noted these resources mentioned in the text: The N=1 "user's guide" put out by Agency for Healthcare Research and Quality and the SPIRIT guidelines published by the Alberta Group. That practical advice could be helpful.
Additionally, it's also helpful that they enumerated the major failings of the majority of current N=1 trials, as well as the areas (of mostly medicine) where N=1 trials have had the most success, like with ADHD.
Another fantastic paper (a little stats heavy) that's hot off the press is this: https://arxiv.org/abs/1901.03423.
The author Eric J. Daza is worth a follow on twitter too, nice guy @ericjdaza