Start with a verse or an intro. This should be the part of the song where you bring in your listener. The beat should be moving already, though you do not need to bring in vocals just yet. The intro could be something as simple as a stripped-down version of the chorus, which we will get to later.
Put in a verse, which is where the lyrics start. Make the beat and the melody subtle so that the rapper or singers words can be clearly understood. The quicker the beat, the more important this is for the sake of clarity. Repeat this for about eight bars.
Insert a chorus. It will repeat several times throughout the song, so it should be quick and catchy. About four bars should do it, and the lyrics should be singable and simple. The melody can flourish a little here; you want everyone singing along.
Make a few modifications for the second verse. This will have the same basic structure as the first verse, but you can add a second melody or change up the instrumentation a little. Whatever you decide to do, don't stray too far from the style you have already established for the song. After this verse is done, repeat the chorus.
Move the song to a bridge. The bridge introduces some escalation or stands apart from the rest of the song. This can be anywhere between eight and 16 bars. As the bridge continues, you can make your song louder, and the vocals can rise up with the beat. You want to make your audience excited for the final chorus.
End with a repetition of your chorus. Loop the chorus twice, so you can keep your listeners attention with your catchy hook, and vary it a little the second time. This will keep it interesting. End with a slow fade-out or an abrupt cut off.