On occasion, lyrics come out perfectly formed. This is rare. Most often, lyrics need to be written, re-written, edited and honed. There are 3 ways to develop lyrics: Find Your Inspiration, Free Writing, and Free Singing.
Once you have identified your inspiration, lyrics can follow. Lyrics need to be meaningful, both personally and universally. The writer, you, need relate to them specifically and the lyrics need to appeal to the listener on a universal level. There are two simultaneous perspectives: Micro and Macro. Lyrics need to connect with the lyricist and singer on a very specific level, and be broad enough for a listener, not familiar with the specifics, to connect.
If you are not clear on what your inspiration is, lyrics can develop from free writing and free singing.
Free writing is taking pen to paper and writing freely every day or so. Upon review, there are phrases and words that stick out with quality, edge, and meaning, and lead to more intentional lyric writing and subject matter. As a songwriter, one needs to write on a theme freely - journal style - and build up content. The building up of content will allow substance to appear for a lyric to provide adequate material for a song.
Free singing is just that: La La La-ing and making up melodies. I came up with this while I was walking around: "It's a Beautiful Day." This is something I haven't done anything with as of yet, and it was a free singing creation of a melody. You can try free singing while jamming with your band. Vocalize vowels, form melodies, and then create words. After a jam, listen back to the recording you made and ask, "what did I say?"...and create the lyrics out of that. U2's Bono is known for doing this.
These are my recommended resources for writing lyrics:
Roget's Thesaurus. This is used for finding word substitutions because you can't keep using the same words.
The Complete Rhyming Dictionary, edited by Clement Wood is also super helpful. There are a ton of rhyming dictionaries out there and everyone uses them.
I-Ching is a Chinese book of wisdom which is spirituality related to the Tao Te Ching. It is a random stick throwing guide to life. I often open it to any page and read it for what it may instruct.
Craft of Lyric Writing by Sheila Davis has been super helpful and is very specific.
The Elements of Style by William Strunk Jr. and E.B. White is a grammatical book and a great reference to utilize when uncertain about how to say something correctly or incorrectly with intention.
How to Not Say What You Mean, A Dictionary of Euphemisms by R.W Holder, gives an alternative approach that is inspiring.
As creating songs is all craft and process, these books inform, guide and instruct. They are always by my side and have been for a while.
Utilize all writing and poetic techniques: alliteration, lists, metaphor, slang, and more. Listen to what other people say and bring it into your world. Eavesdrop. Pick up on news and link news that is unrelated. The art movement Dada did this and made sense out of nonsense.
Use real rhymes. Verbs and lists are lyric drivers. For example, lyrics from my tune "Fifth and Faith" off of Turktunes go:
"Woke up this morning, thought I give my life another try.
Stumbled, fumbled, rumbled with everyone and everything in sight.
Alone in anger, a stranger meets danger."
"Stumbled, fumbled, rumbled" is an example of a good list and rhyme. "Stranger meets danger" is an example of a good rhyme.
Remember, In terms of craft, it doesn't matter if lyric or melody come first or at the same time. Every order works in the process of crafting songs.