Below is an example of a page from one of my sextet compositions.
Throughout the whole chart, I use the same font for text, which creates a unified look. I also do this throughout all of my charts so that the look stays consistent chart to chart.
When I pair instruments up outside of the expected setting or I change the pairings, I note who you are playing with so you know who to listen for before you start playing.
As much as possible, I like to add measure numbers and rehearsal marks to aid with rehearsing and communication. Very often, people will have a question about the music or want to rehearse a certain section or measure and having both measure numbers and rehearsal marks allows for seamless communication. I only include measure numbers at the start of the lines as I found they got in the way of the music when added to every single measure.
Though not prominent in this example, I go through each part double checking the accidentals. Unless music is largely diatonic and in one key, accidentals are more helpful than key signatures. When working with accidentals, I read the parts as if I’m sight-reading, looking for patterns in the music, such as scales or triads, as well as any instances where there may be any doubt as to what the note is. My goal is to eliminate all doubt.
Most importantly, I want the music to look like it sounds. Though all parts of formatting play into this, I show this through double bar lines. Double bar lines mark a new phrase or a notable change, such as the start of a melody. This piece consists of a lot of 8-bar phrases, which you can see pretty quickly thanks to the double bars and having the start of most phrases on the left hand side of the page.