Tips to boost up your skill rank

1. first gear up your best adept set

2. gather your fastest skill. here are some preferred skill for each class.

FS, WA
Charge skill Lv. 9 --> Impact Stab Lv. 9 --> Rising Shoot Lv. 9
FB
Force Assault Lv. 9 --> Impact Stab Lv. 9 --> Force Slash Lv. 9
BL
Assault Lv. 9 --> Impact Stab Lv. 9 --> Double Slash Lv. 9
FA
Freezing Arrow Lv. 9 --> Auqa arrow Lv. 9 (can skill with only 2 even in combo)
WI
Burning hand Lv. 9 --> Freezing thing Lv. 9 --> Magic arrow Lv. 9

The meele type characters can skill with this magic combo:
Freezing arrow Lv. 9 --> Auqa arow Lv. 9 --> Magic arrow Lv. 9

this is from kovyfive of forum.cabalonline.com

The meele type characters can skill with this magic combo:
Freezing arrow Lv. 9 --> Auqa arow Lv. 9 --> Magic arrow Lv. 9
Blader : Assault(lv.9)---Impact Stab (lv.9)---Double Slash (lv.9)
Force Blader : Force Assault(lv.9)---Impact Stab(lv.9)--- Force Slash(lv.9)
Force Shielder: Shield Charge(guess thats the name, lvl.9)---Impact Stab(lv.9)---Flash Draw(lv.9)
Warrior: Assault Skill(Lvl.9)---Impact Stab (Lvl.9)---Rising Shot (Lvl.9)
Note: this also work with FS
Force Archer : Freezing Arrow ( Lvl.9)---Aqua Arrow(Lvl.9)
Wizard : Do Freeze (Lvl .9)---Burning Hand (Lvl.9)---Magic Arrow (Lvl.9)

this is from forum.cabalonline.com by SP4RKZZ

Note: you can also use change force upgrade that you can buy from the port lux instructor.
Tip: you can always use novice magic skills (arrows) while doing your combo.

3. now go and combo up your skills.
Note: each time you use your combo there is an additional percentage of skill points. the higher your combo the greater skill point you gain and 13-14 hit combo will give back the sp used for combo mode.