[DJ DJBLU-]

Leveling is based on exp. points

0~90 / Beginner
91~240 / Trainee
241~550 / Amateur
551~1200 / Rookie
1201~2000 / Sub DJ
2001~3200 / Middleman
3201~4800 / Main DJ
4801~7000 / Pop DJ
7001~9500 / High Class
9501~13000 / Professional
13001~18000 / Mix Master
18001~24000 / Trendsetter
24001~30000 / Hit Maker
30001~36000 / Show Stopper
36001~42000 / Superstar
42001~54000 / World Famous
54001~ / DJ MAX Grand Master

You earn exp points through clearing songs.
The grade you get decides the exp

S = 10 exp
A = 9
B = 8
C = 7
D = 3
F = 1

Lite / Pop stages give you the exp immediately after you beat the song.
Tech mode, on the other hand, gives it AFTER you beat the whole set.
Plat Crew's missions give a lot of exp the first time you clear it, but little afterwards.
Effectors have nothing to do with exp.

So the fastest way to level up would be playing first step and getting all S ranks.