Familiarize yourself with rap songs that are centered around the electric guitar – this will give you a better understanding of the different styles, difficulties, tempos and rhythms of the genre.
A range of rap songs that feature a good variety of electric guitar samples are: “99 Problems” by Jay-Z, “Fight Music” by D12, “Flip Flop Rock” by Outkast, “Put Em Up” by DMX and “Block Party” by Will Smith.
Obtain a good catalog of rap guitar tabs. Whether you are playing a popular rap song or creating something original, you must keep practicing and keep being inspired by rap guitar.
See the "Resources" section for some extensive online guitar tab archives.
Get used to playing repetitive, short or straightforward riffs. Rap music is traditionally sampled around looping samples and quick riffs. Ensure that you can play a riff or a chord progression several times over and that, each time, it sounds consistent with the last.
Master your rhythm. Rap music is generally written and created from the bass and drums upward – both instruments control the rhythm and tempo of any song. The electric guitar therefore must be based on those same strict and tight beats.
Practice, with your hands on a table, “tapping out” the rhythms of various popular rap songs without the music — this will aid your timing and beat measuring.
Invest in an amplifier or a guitar pedal that produces an extensive number of electric guitar effects – rap music is not tied down to one style or sound. Popular rap tracks such as Jay-Z’s “99 Problems” adopt, for example, a very distorted effect, while Dilated People’s “Worst Comes to Worst” uses a very clean sound.