No I am not talking about your gaming skills here, but about your character skills. The more character skills you unlock the better your character will be.
You can keep track of your character skills by clicking on "My info" and then on the "My skills" tab.
Keep in mind that character skills can only be unlocked by playing the public or PVP channel but not in Coop or AI channel.
When you unlock your skills, your character will get extra benefits like faster reload for the rifleman class, faster sprinting for the pointman class and extra pistol ammo for the sniper class.
So take the time to unlock your character skills, as they will make playing easier and improve your AVA experience.