combos:
lvl 1 - lvl 9 -> learn martial art combo from NPC beggar. u can only use bare knuckle or newspaper or any weapons that can be use for all classes.
lvl 10 and above -> learn specific class combo skill from the class skill NPC. if youre a warrior then you gonna learn at tower of training at lime.
before you can do combos, you need to fill up the combo gauge first ( 3rd bar when u put ur mouse on ur char ) when the bar is blinking red, then u can start doing combos. just choose an enemy, before the weapon hits the enemy press A, S or D and keep doing that.
http://sealonline.wikia.com/wiki/Combos
warriors need to max out all the combo skill and concentration ( fills up the combo gauge faster ) they also need to learn the single target offensive skills. for the quick slash, let it stay at level 3, u dont need to max it. but after that u do need to max it. u also need to learn enrage, its an attack damage buff. do not learn the AoE skills... they are worthless.