You can write a song about just about anything. Keep the chords and melody simple. Don't be afraid to rewrite. First, you must create a short and concise sentence that describes what you want to COMMUNICATE in each section of the song.
In addition, you should keep in mind that stanzas have to shape your great idea of a chorus. Your chorus should be the “I said all that to say this section of the song”. Most of the musicians I know start with a part of the melody first. Often, it's a chorus, but it can be the introduction of a song or even a verse.
When you have one or two parts of a song, you can connect and rearrange them as you please. Then, once you have a basic melody, you can start playing with the lyrics. When you have the ingredients and the overall flavor in mind, you can start developing your recipe for writing songs. One of the best ways to do this organically is to experiment with ideas to see what stands out.
Whether you're a novice or an expert, you'll continuously learn to write a better song than the last time. If you want to start as a composer, you first need to know how to write a song for beginners, where to start, how to finish and tips to help you move forward.