Learning Transitions in complex songs
I am trying to find a way to solve a problem in my learning particular kinds of songs. These are more complicated songs. They are not just stanza, melody, repeat. One I have been working on for a long time is O Holy Night. I am really not one who plays from tab. I use it in initially working on a song, but as soon as I know parts of it, I don't want to look at the tab. It's not for any logical reason; it's just how I am. I may try to follow the tab, but once I know a significant part of the piece, I forget to look at the tab. Then, when I need it, I don't know where I am in it.
I can probably play 90% of O Holy Night beautifully (if no one is looking). But, I get to the end of the first part, and I am flowing with it, then there's the D7 chord and the melody moving to the second string for the accidental G#. And, no matter how many times I tell myself, at the start of the song, that it's going to be there, and I forget it's there, and the timing gets off.
So, if anyone else has had a similar problem with this song or one like it, how did you help yourself to remember that there's this beautiful, but subtle transition at that point in the song? It's like I need some sort of mnemonic to get my attention to detail up at just that point where the transition is going to be next. What do you do about this?
All thoughts will be greatfully received.