Besides attributes, your skills, talents or spells, and specializations define who you are and how effective you'll be in combat.
Each level you will get more powerful as you add points in these areas. For more specifics on skills, talents, and specializations, see the Classes section.
Skills
All three classes share the same skill tree, which includes the following: Coercion, Stealing, Trap-Making, Survival, Herbalism, Poison-Making, Combat Training, and Combat Tactics.
Whether you want to focus on persuading others, detecting enemies, crafting health potions, or learning combat tricks, among other things, you gain skill points every three levels (or one every two levels if you're a rogue) to explore the skill tree.
Because you will probably be able to fill out only two skills, put some serious thought into which ones you want to master.
Talents and Spells
Talents are specific to warriors and rogues; mages learn spells. They are the bread and butter abilities of your class, and you will rely on them more than anything else in combat.
You can't take everything, so choose talents/spells that fit into your play style. For example, a warrior can dual-wield weapons, fight with weapon and shield, rely on a two-handed weapon, or strike at range with bow and arrows.
All talents don't complement each other; choose a path and stick with it to unlock the better talents/spells at higher levels.
Talents require stamina to use, while spells cost mana. While stamina and mana do regenerate, leaving certain talents/spells activated will not allow a character to fully regenerate their stamina or mana.
This could prevent the character from using other talents/spells when starting a new encounter, so always keep an eye on your stamina/mana levels before and during a battle.
Specializations
You unlock your first specialization at level 7 and your second at level 14. Specialization gives special bonuses to your attributes and opens up a new chain of talents unique to the specialization.
They are very powerful abilities in the right situation. Specializations for a warrior include berserker, templar, champion, and reaver.
Mage specializations include spirit healer, shapeshifter, arcane warrior, and blood mage. Rogue specializations are ranger, bard, duelist, and assassin.