I’ve been making an effort to be more observant about my mistakes, especially repeated ones, and to reflect on what was happening in my mind and body when a mistake happened. (See my 15-Jan-2024 post, “Juicy Mistakes.”)
Here is an example from May, from the Concord Orchestra’s season finale. This is from the horn 2 part for Mozart’s Violin Concerto No. 4. It is Horn in D, so I was transposing. I noticed that I was having repeated trouble with the first note on the second line. I missed it in a similar way in two different rehearsals.

From Mozart, Violin Concerto No. 4, K. 218, Horn 2 in D
After the second miss, I was initially puzzled, as there didn’t appear to be anything technically difficult in that measure. After I replayed it in my mind, however, I realized what had happened—the line break caught me off guard, because I hadn’t looked ahead to the beginning of the next line to see what was coming.
I thought for a bit about what to write on my part to prevent this mistake from happening again. Here is what I settled on—the standard “eyeglasses” mark, paired with a backwards-curving arrow.

Marking a hazardous line break
This mark worked very well for me. It’s easy to write and recognizable. When I see it, I know that I need to look ahead early to the beginning of the next line.
I soon became aware of the same issue occurring elsewhere, and so I used the same mark. Here’s an example from earlier this month, at the Assisi Performing Arts Festival.

From Reinecke, Trio for Clarinet, Horn, and Piano, Op. 274, Horn in F
At some point, I hope that I will need this kind of mark less often, as I learn to do this look-ahead automatically. For now, though, it helps.