Think About What Ideas You Want to Express
This is the most important step. Music is great at taking big ideas and expressing them while being wholly coherent. This is much more difficult in writing and poetry. So don’t be afraid to start with big ideas, worry about specifics later.
Before you do anything, think of that thing you love, what specific idea do you want to write about? Write them down and narrow it down, pick one that will be the center of your piece. Every step in the process should have this idea (and sub-ideas) in mind.
Remember, it’s about what the audience will feel, they are a crucial part of the pre-writing process.
Improvise on those Ideas
Now that you have an idea of what you want to express, think of the audience. What emotions do you want the audience to feel? Start by making a list and narrow it down to 2-3. Then get on any instrument, it can be piano, voice, electronics, MIDI, any medium that lets you improvise.
Remember, you’re not writing the piece yet, you’re just digging for ideas. Don’t worry about any playing technique, you just want to get an idea of what sounds should embody the music.
Sketch, Sketch, Sketch!
Once you have a basic sound profile, now is the time to start writing ideas down! You are not at the stage where you should worry of compositional technique. You should instead be solely focused on those ideas and emotions you want to share. Remember, it’s about what the audience will feel, they are a crucial part of the pre-writing process. With all that in mind, write some melodic, harmonics, motifs, and connect them to the ideas you want to express. For example, when you want to show something falling, Chromatic descents are the most familiar signifier.
Once you are done, you should have a musical thesaurus where words, ideas, and emotions are paired with musical ideas.
Write the Piece!
It is from here you can start your first draft. Now you are in a position to use your musical thesaurus with your technique to create a powerful expressive piece just be sure to always have those ideas in mind