From: San Francisco Vocal Coaching's "Singing, Songwriting and Performance" Class (I've also taught it at Princeton University.)
How To Write A Song, Exercise 1 (for beginners, or for writer's block):
Write a letter to someone you feel intensely about something you feel intensely about. If you don't feel intensely about anyone or anything, pretend you are someone else: a character from a book, a play, or a painting, or someone else you know. Use a spiral notebook and write six to ten single sided pages on the right hand side, leaving the left sides blank. Don't stop writing; even if you have to write, "I don't know what to say." Write "I am writing to you in blue ink. The sky is gray. There is a fly on the wall..." Once you start, keep writing the entire letter in one sitting, preferably ten pages.
When you are done, read your letter over, circling or underlining sentences, words, fragments that jump out at you (use a different color ink, or highlighter). They do not need to be brilliant. You just need to notice them. As you are doing this, you will probably have interjections, other things you want to say, tangential thoughts, random words. Write these down on the blank page on the left hand side. Take these new thoughts as far as you can go with them.
If you no longer have room on the left page after this, rip out a third page and put it above your letter pages. Pick words in your letter that you have underlined or circled and list rhymes, and secondary rhymes. Other words may come to mind as well. Write them down. You may notice every time you write down a word, another pops into your mind to take its place. You're not just making a list of rhymes:
wait,
state,
hate,
bait
Rhyme wait with stay, or strange, bathe... paying attention to the long ay sound.
Rhyme water with shoulder, or with her and wither.
In lyric writing, there are times you want to work against landing on the rhyme too hard, over and over. See what happens to your lyrics when you don't do it, give yourself choices. Try rhyming within the lines, instead of landing on them at the end of each line. See what sounds better to you, especially as you begin to find your melody. If melodies come to you as you are sculpting out words, take a moment and record them. The words you begin to sing may be placeholders for other words. You can always rewrite them. Allow the words to change. Keep writing them down, so you do not have to worry about losing them. Think of your words as clay. They can be molded. They can be torn apart and put back together again.
List word associations. The word "water"may make you think "thirst," or it might make you think "underwater, drowning, swimming, floating." The word "thirst, " rhyming with "first" may make you think of the first water you drank in a certain place or with a certain person. A lyric may come to you though these associations. Follow The Words As Far As They Go.
With the pages of your letter, interjections, rhyme schemes and word associations -- you have a lot of clay to begin to sculpt out lyrics. You will not be searching for words in the air. You have words in your hands to work with, that contain your own detailed thoughts -- so they should not sound cliché or trite. They should sound like you. You may have lyric ideas for many songs, in fact. Save These Pages.
While you are underlining and developing your rhyme schemes, you may have already started coming up with melody. If at any point, you get inspired, leave the exercise and follow the inspiration. You can come back to the exercise.
Once you have recorded any of your melodic ideas (if you haven't had any yet, don't worry, they will come), take a song you know you love and start using your words to write new lyrics for that song. You will follow a strong structure. Diagram the song you chose as a model. In each verse and chorus, for example, using your imagination, decide "where you are" and "when you are." Boil it down. What is the question or command in each section? If the song travels from this morning, to yesterday, and then to tomorrow, you can explore traveling in the same direction on your song, or shuffle the order of events, start with yesterday, move on to tomorrow and finish with this morning. If the writer is asking "Where did you go?" in verse one and commanding "Come back to me!" in the chorus, "Do you remember the moment we kissed?" in the second verse, and "Come back to me!" in the second chorus, you may want to use those questions and commands as guidance. Or come up with different ones. What would the verse look like, if you painted it? When you listen to a song you love, do you see something? Does it give you a picture? If so, when you're writing a song, you also want to see the pictures. No one has to know what they are, you don't need to be explicit, but seeing the scene, can help you finish the verse.
Once you are done sculpting your lyrics to your model song, you will then change the chords, and change the melody completely, change the rhythm, key, tempo, etc.. Your lyrics may need to change as you work them into a new song, as your new melody now begins to lead the words and make them sing. Follow the melody. Explore where it might go. What happens if you remove some of your words, how does it sing differently? Allow the words now to follow the melody as far as it will go. A song is words being sung. In this exercise you are weaving melody and words. Let them shape each other.
Though you are changing the music completely, keep the song structure in mind, and only leave it because you have to. Songs have different shapes. If you know you love a song, then you are starting with a structure that appeals to you. Study the song, how many lines in the verse and chorus, does it have a chorus, or maybe a tag, is it through-composed? Where are the rhymes, does it have a bridge? Are there musical interludes, where does it take a breath, where does it move more quickly into the next section? What are the hooks of the song, meaning what is left in your brain after the song has been sung? What do you not forget? Where is it? Is it just the words you remember or the melody or both together?
If you don't know about notes and scales, notice high notes and low notes - maybe the verse starts out low, but when the chorus comes in, it jumps up to higher notes, or the opposite. Maybe there's a section that suspends or holds out a bit, making you want to hear the chorus more when it comes in or maybe there's a lot of space somewhere. You might notice the beats in each line, count them, see how many there are. You don't need to do everything the song you are emulating does, but it's helpful to notice.
This is a long process and it will take you a week to write a song using this method rather than a few hours. However, it is a great exercise, and depending on your letter, you may find that you have lyric ideas for many songs. Modeling your song after another song is a similar process to an artist painting another artist's painting. Emulations and even imitations allow you to absorb how a certain composition, brush stroke, or color serve a work's purpose. Changing the melody, chords, tempo allows you to take that process a step further and truly have an original work.
If you study the sculpture "Ugolino" by Carpeaux and compare it to Rodin's "The Thinker," you might agree that "The Thinker" is an emulation of "Ugolino." There is much of one in the other, but both are original works.
Many great songs come from swift moments of inspiration, you will write those. This process is a reliable one that takes more time, but it will produce - at least - a good song, and maybe a great one.