Choose a subject and mood for the song. This is important to do before selecting or creating an instrumental, because the mood of the lyrics needs to be reflected in the background music. Sad, reflective or otherwise poignant songs are often performed on slower instrumentals, for example. Faster, more upbeat rap songs --- like those played at parties and clubs --- may have more shallow subjects, allowing listeners to enjoy the song with little concentration.
Select a basic idea to be presented in the hook. The idea should summarize the song's verses, though it doesn't necessarily need to be written after the verses. Writing a hook first can assist lyricists in staying on subject while creating the rest of the lyrics. The hook's main theme or idea should be expressed in two-to-eight lines, with catchy phrasing and basic rhyme patterns.
Create the hook's lyrics while bearing in mind any time constraints set forth in the song's beat. Hooks are commonly 20-to-30 seconds and are repeated between every verse. Avoid cliché rhymes that are present in other songs or that are easily predictable. For example, the following words are generally considered to be overused in rap and should probably be avoided: girl and world, hurt and earth, dark and heart, and so on.
Review and revise your hook. It's the song's first and last impression; possibly the only part that fans will remember. Analyze the hook's rhyme pattern for consistency. Each line in the hook should be relatively equal in length, and devoid of any filler material. A thesaurus may help when attempting to replace specific words for the sake of originality.
Record the hook. Confirm that the lyrics sound the way you planned and match the instrumental's tempo. Hooks may be either sung or rapped, depending on the artist's preference. Audio engineering software may be used to tweak notes in sung hooks, or add sound effects to the vocals to better distinguish the hook from its preceding verse.