Most of my thoughts on score prep can be found in this checklist on Scoring Notes. I wrote the list, and Scoring Notes editor Philip Rothman added links to some really interesting articles that go into detail on many of the topics. As the editor’s note at the top suggests, many of these are Sibelius specific, because until 2017, the publication was Sibelius-focused.
Here’s an article on program notes from my own blog. Regardless of how you feel about the importance of program notes, someone will inevitably ask you for a note to put in a program or to speak about your piece. In either case, it’s a lot easier to put your thoughts together while the piece is fresh in your mind. Even if you don’t publish the note, it’s a nice reference if you ever need to speak about the piece to performers or audiences.
If you need to include any graphical elements in your score, here’s a tutorial I put together on graphic notation. I demonstrate using Sibelius and Adobe Illustrator, but the same process will work in any scoring application and with any drawing application.