The energy behind the vocal performance can make or break your song with your audience. Rhyming is a necessity. In the studio, you've likely learned about doubling and tripling vocals on the chorus, but you can change it up a bit. Try performing the chorus like you are chanting it with an audience at a football game. You can do this yourself by putting different levels of energy into each take you record. You can also invite friends over to perform on the chorus with you. Three males, three females or a mixture can help you achieve the "crowd-performance" effect on your chorus.
Hire trained singers to perform the chorus. Your singers can be male or female, and they can add a true rhythm and blues or soul flavor to your chorus. Recruit singers from your local university's music department, from neighborhood churches or at nearby performance venues. During recording, use harmonies wisely by not overusing them, and make sure they are crisp and distinct. If the singer can provide a five-part harmony, experiment with it. You may discover a very powerful arrangement for your chorus this way.
If you're really feeling stuck on the chorus, spend some time freestyling with it and record the freestyle sessions. Save money on a studio session by recording the freestyles on a small digital recorder or cellphone voice mail. Listen through the recordings, and pull out the bits that stand out to you. Play around with them some more, then try rapping or singing the entire song just like you would at a live performance. Move with it while you're singing and rapping. If the chorus is truly catchy, you will feel its potential during this type of physical freestyle rehearsal process.
Get an outside opinion. Perform at showcases, get local DJs to play the demo versions of the song and listen to the call-in responses from listeners. Some songs morph through many versions before becoming the final gem you put on an album and send to radio stations. Knowing this going in will help your inspiration flow freely and without pressure. Have fun working on the chorus, and keep in mind that your audience is going to give you the best framework for what works and what needs more work when it comes to your chorus.