Structure IS NOT very important, as DOS said if its all over the shit its not good, but if theres niot much diference its alright.
If it i structured better 95% of the time it will flow better ( unless the words don't rhyme )
This can be done by just shortening down the punches, and making them hard hitting but nice and short. If your not sure if it flows, actually speak the words out in a rap speed and see if it flows.
PM me if you want any other help, or hit me up on AIM: Bkast00

pce