I’m currently in the process of submitting stories to various paying markets, and most of the big SF magazines, while they take email submissions, still want the files to *look* like they came out of a mechanical typewriter ca. 1970 – monospaced font, double-spacing and all.
This is a bit of a pain to do, and Google isn’t much help – if you Google Standard Manuscript Format LyX, what you get is people asking how to do it, and other people ‘helpfully’ responding “you don’t want to do that, LyX’s default is much prettier than that”.
But I’ve eventually found how to do this with a lot of Google-fu, and it turns out there is a simple template for LyX to do this. You will need the SFFMS LaTeX package, which should have installed with your LaTeX distribution, but if you want to check then it’s part of the package texlive-latex-extra in Debian-based GNU/Linux distros (other OSes may vary).
All you need to do then is to visit https://github.com/kcyarn/sffms-LyX-Layouts and download the two files sffms_novel.layout and sffms_short.layout. Copy them to the directory in which LyX stores its layout files (on Debianesque Gnu/Linux distros this will be /usr/share/lyx/layouts , but you can see it in Tools-Preferences-Paths in your copy of LyX).
Then in LyX go to Tools-Reconfigure, and restart LyX once this has finished. Now when you start a new document, go to Document-Settings and in the Document Class dropdown choose either SFFMS (Short Story) or SFFMS (Novel).
Kinks post later tonight or tomorrow morning.