I'm not talking about a specific song I'm trying to write. I mean generally. Occasionally all the components come to me by inspiration (the hook, the verses, etc) but usually I'm missing a piece of the puzzle and can only come up with what I want the song to be about. Oh yeah, I and I can't write music, just lyrics.
As in, how do you bridge the gap between song topic to actual lyric construction? I would suggest you just start. Begin writing down any phrases or words that capture the emotion or idea that you want to capture. Then see how you might bridge the gap between those words and phrases. Don't worry about beat/tempo/rhythm etc; you can play with the mechanics later. It's just the same as any other writing project. Start somewhere and go from there. Nobody can give you a magic cure to enable you to suddenly be able to write exactly what is on your mind. That's a skill only you can cultivate for yourself. We can help you with specific phraseology and syntax issues but it's up to you to get something down on the page in order for us to do that. Edit to add: Maybe your strengths lie in an area other than song-writing. Are you particularly music-minded? If not, perhaps the themes/ideas that come to you might be better explored in a short story or flash fiction?
It's definitely a challenge if you can't write music, but certainly not impossible. As a matter of fact, more recently I've relied less on having a solid foundation of chord progressions or anything before getting started. But one of the things I always need first is style--how is the song going to sound? Is it heavy, is it upbeat, is it acoustic, etc? That gives me a feel for melody. I also need to know time signature--typically 4/4, but occasionally 3/4 or some other odd time if I'm feeling adventurous (this will tie in to style as well--if you're writing a prog rock song, 5/4 and 7/8 are much more common, but if you're writing a punk song, typically stick to 4/4). One I have the basics down, I still need to understand rhythm and structure, at least a little. Whether I'm writing chord progressions or not, I still have a general idea of how the song is going to progress. I can tap out a rhythm on my desk. With that rhythm in mind, I can start to form melodies, and that's where the lyric writing starts. For me, I need a melody first--even if it has no words. So I think of the rhythm I have and just hum along to it. Think of what songs in that style sound like. How do other artists write their melodies over similar rhythms? If it's growling metal, melody is less important--you just need a chuggy rhythm. If it's pop-punk, you need some kind of catchy hook in the melody. Then once I have a melody in mind and a subject matter, as you have, I can start to fit words into that melody. Often I'll pick up ideas from lines in other songs, or thoughts I have throughout the day that may or may not translate directly into lyrics but give me a vibe I want to try to recreate. There's no easy solution to coming up with words, though--you just have to do it. Having the melody in mind makes it a lot easier, though, I find. In the few experiments I've done where I write words with no melody and try to force them in later, it hasn't worked. But that's just me. So that's my process: Style, then rhythm, then melody, then words. And listen to plenty of other songs in that same style while you're trying to write--it'll really help you come up with rhythms and melodies that fit that style. Hope that helps
I did write something decent once. I need to put to music though. https://www.writingforums.org/threads/song-from-a-culture-of-dragons.150956/
The piece of the puzzle you're missing is the music. Lyrics are just another part of the music. Basically you start by looking at what the music suggests rhythmically. That syllabic road map becomes your meter scheme. Then you try several sentences, phrases, words, what-have-you, that all more or less fit the meter scheme, until something sparks you to write entire stanzas that do interesting things with the meter scheme. You can do this the other way and start with the lyrics, but A) Starting with the music inspires much more creative rhythms and B) You'll find, more often than not, as soon as someone tries applying your lyrics to music, they'll end up shaving words off, adding words, etc. to fit the music, because as I stated, lyrics are just another part of the music. Time to find a way to make music.