i've been all over the place in the past with what i write my lyrics to, but lately it's been either a moment of inspiration while playing my guitar or singing a tune + lyrics into my state of the art recording setup (my smartphone
).
i think the most important thing is capturing inspiration in the way that works best for a person, but i think there are few basic ideas to consider, with the disclaimer that art is subjective, whatever sounds good, etc...
could just be me, but i feel that poetry doesn't always translate well to lyrics. by "well", i mean not awkward to sing (or listen to). i've written both and they have mostly stayed in their separate corners, and it's been a rare that a combination has turned out to be what i consider "good" (always predictably metered poetry heading into the lyrical category, and usually with some alterations).
i think that is because lyrics are usually written with a melody in mind, even subconsciously, and poetry is written against a meter, or for more abstract forms, against an emotional balance of words vs. the shorter, regular rhythm of "western" music. to counter this, though, you could say that lyrics are just a form of poetry set to rhythm rather than meter.
i also think a big part of lyric writing is intent: is it self-expression, is it carefully crafted words, or is it just the distinction between one great groove and another (and there's nothing wrong with that). listening to top 40's radio (which i rarely subject myself to
), i'd say that a lot of it is the third option, but even then, there's some really inspired lyrical hooks out there despite the "hit factory" vibe.
i think that intent helps narrow down approaches - i think it would be easier to write lyrics before or during a song that is basically self-expression, and harder to carefully craft words to a finished instrumental. and there's definitely a science to it, or at least a psychology, if you are looking to go the crafted route.
i totally agree that pushing yourself is the best way to expand your talents. trying things you wouldn't normally do, order of writing you aren't used to, typing vs. writing, etc. i think another important thing is realizing that writing lyrics is always practice for next time. being able to recognize when you've written something that is inspired, and being OK letting go stuff that isn't.