“When writing a hook or chorus, what do you focus on the most?

 When writing hooks and choruses, we focus most on the listening emotion and memorable lines, and the hook's job is to get the song stuck in the mind from the very first listen. 

The more emotion you put into your hook line, the better your rap song will be. 

Hook means repeating the interesting part.

First hook the short line, then hook two lines, this will be more effective. Your rhythm and flow should both be  consistent And this is more important in rap songs. 

You repeat one or two words over and over again 

So write in simple words, strong emotion and clear vibe. Your flow should be so good that people listen to the song and sing its praises. 

Your hook line should be in sync with the beat If the beat is heavy, the hook should be powerful; if it's soft, it should be emotional. And a good hook shouldn't sound boring even if it's repeated. 

You have to make sure that your hook line does not bore because people will like boring hooks. Your song makes people feel good so that people watch it again and again. People should listen to rap songs.

 People who write boring hook lines, no one likes their rap songs, so improve your skills.

Keep working hard, your hook line will improve. Only those who work daily will improve.