question about scores

[W_I_N_N_E_R]

Ok question i been wondering for a while now. How do the high HIGH scorers get such high scores? what factors give them these scores. Cause some song i get near perfect (like only 4 goods and everything else perfect no miss) yet i still only get say 50% of the highest score. Also, i noticed something during Fett's Vette where there seem to be secret keys at the start. Are those secret keys in the levels that gave the experts the extra scores? srry for sounding like a retard...