A real rapper needs to have advanced metaphors, wordplay, flow & delivery, vocabulary, rhyme structure, raw emotion and always needs to have complex lyrics, it's important to use words in the dictionary noone ever heard before in my opinion, that will label you as an intelligent rapper.
You also need to be capable of many things, all that commercial bullshit you see on MTV with the BLING BLING and such is fake, you need to be able to rap about all different subjects and topics.
I can't stress how imporatnt the complexity in your lyrics is, that's what seperates you from the commercial bullshit you get on MTV.

Here are some people that define what I just said:

Cage, Copywrite, Mr. Lif, Murs, Common, Camu Tao, Aesop Rock, Spice 1, Brotha Lynch Hung, C-Bo, Tech N9ne, Motion Man, Planet Asia, Despot, Prime, Alaska, Doujah Raze, Slum Village etc.

If you don't know these people, research them.

Useful Links:

www.ecrecs.com, www.definitivejux.net, www.trilogyrecords.com, www.threshrecs.com, www.undergroundhiphop.com...

That is real rap, that's all you need to know.