Print a list of the lyrics you wish to practice. Whether you've written the lyrics yourself or are trying to perfect your version of a classic hip-hop track, having the lyrics in front of you is important.
Play the song's beat on a computer, stereo or portable MP3 player through headphones, if possible. If you've written the lyrics, you may not have music to go with them. But, if you're practicing a popular rap, try to find an instrumental track to the song to play as you practice. If you're experienced in working with audio software, loop the beat behind the first verse so you can practice it over and over without having to keep stopping and restarting it.
Work on one rhyming couplet at a time, rather than trying to memorize and deliver the entire song at once. Rap the couplet aloud while noticing your timing. You can perfect your delivery, if needed, once you've mastered the timing. Rap music is all about rhythm, so it's important to learn the lyrics and their rhythm.
Add extra rhyming couplets one at a time until you've learned the first verse. By now, you should be able to rap the entire verse with the correct timing and enunciation. Learn the chorus, if applicable, and subsequent verses in the song using the same method.
Work on showmanship routines if you're planning to enter a rap battle or are going to perform the song in front of a crowd. These routines can include dancing, jumping, posing and pointing at the crowd. If you want to have the crowd interact with you, you can point at it when it comes time to rap your chorus.