I have previously recommended creating your own style sheet to aid you when you are proofreading. If you aren’t sure where to start, I have produced a sample to help.
The layout is the same as the one I use when compiling a style sheet for the projects I proofread. All my non-publisher clients get a copy of the style sheet for their own reference once I have completed proofreading.
The sample is for a made-up project, but it should give you an idea of the things to consider. I have also included some formatting and layout elements you would need to think about as you get ready to publish (e.g. chapter headings and page numbering).
I would advise recording the decisions you make as early as possible (particularly the basic ones such as is/iz suffixes and single or double quote marks). If you do create a style sheet and later employ an editorial professional, send them a copy. It’s really very helpful!
I have uploaded a blank copy of the style sheet for anyone’s use (although if you share it I would appreciate a link back to my original). The sample is for a novel, but you can make adjustments to the blank copy for any writing project.