Firstly....someone has to a dope rhyme shceme.I absolutely hate that Tupac/50 one syllable shit.

Then it's about delivery.If ya making a violent song...bring intensity and roar in your voice.If making a soft,love song...have a eminem/mockingbird type a delivery.

It doesn't matter wat topics the person raps about.As long as it's good.Even if the person is not a killer and is pussy...if he wanna rap about violence...then let him.I hate when someone raps about street and shit...but then people say "OOOH...but he isn't real!!!".
We don't know them...so let's not judge whether or not they are real or fake.I belive someone can rap about anything they feel like.