Maintain your sex appeal. In addition to having good vocals and the ability to rhyme, rap artists spend a lot of their time performing in front of people. Local shows at clubs, house parties and parks put a rapper up front and personal with her crowd. It is likely that males will dominate the crowd. It is also likely that those males will want to watch an attractive woman rap more than one who is not sexually appealing.
Appear unique. Develop a personal style that is all your own. In the early days of rap, female MCs would dress and act almost exactly like the guys. The fusion of rap and pop music has forced female rappers to stand out from the typical acts in either genre.
Display self-confidence. Rap music began as braggadocio street-corner boasting, while a DJ played a record. That sense of ego is what makes the genre so unique. A girl rapper must be able to display that same sense of bravado, lest she be considered too weak for the rap game.
Write your own raps. Nothing gives a rap artist more credibility than being able to write her own rhymes. The better and more unique the rhymes are, the more original the female will seem. Don't rap about exactly the same things as the guys. You can rap about money, cars or life, yes. But when rapping about sexuality, as rappers often do, highlight the female perspective with your own particular thoughts.
Control your image. Know who you are as a rap artist. Be comfortable with being a female rap artist and all that comes with it. Have great lyrics, stay sexy, be original and be exciting.