This is a really well written guide, recently got into solo journaling games, and by recently I mean yesterday where I basically ended up writing a whole short story by playing 32% by Lostwaysclub.
I like this guide, as it explains some things you can to do what solo journaling games do, without having to attach yourself to a system. I like 'solo roleplaying' I guess because its essentially a elaborate system of writing prompts- and I write better when prompted.