Compose an intro with an instrument. This can either be fast-paced or slow depending on the mood you want to express. Don't give away too much of the song. Lead into it by only giving a taste. Skip this section if you are not using any instruments.
Write the first verse. The length of each verse can vary depending on how long you want the song to be. Compose a melody with an instrument or your voice and hum the tune to come up with a rhythm. Write lyrics that will fit this rhythm and theme of the song. Create a pre-chorus two-thirds into the verse by adding tension, as if you are standing at the edge of a cliff. Use diminished and 7th chords to enhance this tension.
Write the chorus. This should feel as if you are falling from the cliff. Make this section of the song catchy and memorable. Compose the chorus so that it is slightly shorter than the verses. Repeat this section in your head. Tweak the wording if it does not sound memorable in your mind. Create a pre-verse by adding tension to the end of the chorus as well.
Write a second verse. In some cases you can simply repeat the first verse. Continue to stick to the theme of the song and add onto what was sung in the previous verse. Insert another pre-chorus by adding even more tension.
Repeat the chorus. Insert a solo at the end of the chorus. Although this is optional, it can be used as a transition to the bridge.
Write a bridge. This is a separate section used to strongly enforce the message of the song to the listener. The bridge is often the heaviest and one of the most emotional sections of a song. Think of this as hitting the listener over the head with the theme of the lyrics before the final chorus.
Insert a breakdown. This can be the chorus or a shortened third verse that is sung softly. Lead into the final chorus, which is the most emotional section of the song. Add multiple harmonies and driving solos. This chorus may be repeated several times.
End the song with an outro. Drop the full lyrics of the chorus and blast the instruments toward the end. Insert an optional final solo and repeat bits and pieces of the chorus and verses until the music fades.