No doubt you'll get more polished advice from the more polished writers among us, but as a quite new songwriter myself, I thought I'd share a bit about my experience so far.
It just kinda started happening to me. Having a ukulele in my hands a little over a year ago just opened some sort of door I had no idea was there, and songwriting starting coming out of me. So my experience has been very organic.
The first time it happened, an idea just popped into my head. Somebody said something one day, I forgot about it, and a few days later, out of nowhere, a song concept, and, I think, one line of lyric just appeared, unbidden, like the proverbial lightbulb.
Most of my songs have started this way ... a single idea or concept, and/or a single line of lyric ... usually prompted by an
experience or
event or
conversation or
something I saw online, or maybe
a thought prompted by a Season theme. Once I was just noodling around with some chords, and found I could only keep that up for about a minute before
words starting coming out of me. A few times I've written to prompts that were not personal to me, including for
Season 124. I'm pleased with those songs, but I find I'm not drawn to play them much afterward.
What happened that first time was that it occurred to me, hey, I have an instrument I can play with my hands. I know a handful of chords. I know a tiny bit about how those chords sometimes seem to get put together into songs. (Really, almost nothing about that, that first time ... mostly I just knew a few chords.)
So I picked up the uke, and played a chord. If it sounded good, and fit what my voice tried to do, I attempted to use it for something. If not, I tried a different one. That first song was very "hunt and peck", because I really did not have much at all in the way of tools to do anything else.
Over the next few days, bits of melody and words began to form around the chords, and as I went out for walks (always with a voice recorder on me), I'd experiment with bits, keep the best ones, discard the rest.
If I liked a line, I'd look for other lines to fit with it, melodically, lyrically (meter and rhyme), and story-wise. Once I had a bit of raw material, I sat down with ... paper that first time, pre-iPad ... and attempted to assemble my song. Gradually, I fleshed out verses and choruses and a bridge, and assembled them in a way that made sense and I was happy with. Ultimately from this process, a complete song emerged.
That first song was actually more complicated than most of my later ones have been ... I have no idea why ... it just happened that way. I ended up needing
actual sheet music (I discovered the wonderful, free, noteflight.org that night) to follow the melody I was creating, and the chord changes I made from verse to verse and chorus to chorus. These days I usually keep that stuff simpler, and since then a simple chord-lyric chart and an audio recording have sufficed me.
Most times since then (I've written, I think, 13 originals - about one a month - and a number of parodies and mash-ups), my process has been similar.
It nearly always starts with a single idea, concept, and or lyric line. Then I get out the uke and start noodling and see what comes. I audio-record (on my awesome Sansa Clip voice recorder) to capture the melodies and rhythms, and simultaneously write down the chords and lyrics as I come up with stuff, these days usually on the iPad.
[I've set up shortcuts for chord symbols on the iPad to make typing them easy. Like "g." produces "(G)" on the pad, "dm7." produces "(Dm7)", etc. I just type those in the flow of the lyrics, and the chords appear in parens like that between appropriate syllables or words. Once the song is complete, I type up a more readable chart, usually with the chords on a separate line above the lyrics, in Word, and then save it as a PDF ... which I read from the unrealBook app on the iPad. But I digress.]
Once I have a bunch of material down in more or less random order at this point, I start to assemble it into some sort of structure, and then fill in what's missing to make a complete song. Usually by this time, I have at least some idea what story I'm trying to tell ... so that guides the order of verses, choruses, and sometimes bridge(s), and which bits of lyrics go where and in which of those elements.
At some point, it looks / feels / sounds complete to me, and I call it done. And go make the video.
These days (partly through playing, but mostly through writing, and talking with others about writing), I've learned a bit more about the typical ways songwriters assemble the various structural elements and how to put chords together in an order that sounds good.
I still have absolutely no idea how to write melodies ... I just play chords and attempt to sing some words, and the melodies just kind of emerge out of that. I'm pleased with the results ... I just mean that that part of the process for me happens organically ... I don't feel like I have the least bit of formal knowledge about it, nor do I apply much thinking to producing them. I just sing, and keep what I like and tweak what I don't until I do.
Bottom line:
I highly encourage you to get out a uke and play some random chords, and attempt to sing your lovely poem, and just keep playing around with it until something you like emerges.
And then, next time you feel the muse, do it again. The more I do it, the more I learn, and the more confident I become that I can do it again. And you will too. Just like playing ... the more you do it, the quicker you'll learn it.
Oh, here's that first song I wrote ... at Season 88 ... 4 weeks after my first Season, 8 weeks after I first picked up a uke. And
here's the sheet music ... it still doesn't have a chart!