Songs should have a clear message in the hook, think cliches like “you can’t handle this”, “I’m the best”, “never gonna stop me”, etc. Vocalese hooks work as well if the track itself has the right tone. Keep things positive; confidence doesn’t mean hating on anyone else for not being as awesome as you are. These tracks should also be authentic and believable on an artist level, so if most of your catalog is about love and breakups this one might not be for you. Retro vibes are great for this.
