Knowing your target audience is vital when advertising a new artist. The genre of music the Artist produces should give you a strong indication of what sort of demographic will purchase their music.
Jessie J's genre of music is Commercial/pop-ular/R&B. The demographic for this genre is stereotypically...
-Majority are females
-Fashionable-care about there appearance
-Gossip magazine readers
-Crosses over all races
-Likely to spend money on new artists