Speed
Improvements to speed increase your rate of movement and the amount of agility available to your character during combat. Your speed skill also controls the quickness of your attacks using weapons such as rifles and swords. This allows you to land more strikes in a given time period.
Accuracy
Upgrades to your accuracy skill increase the amount of damage you inflict upon your enemies with ranged weapons. This skill is critical for characters that prefer using archery and firearms such as pistols.
Guile
The "guile" skill is similar to intelligence or "wit" and is useful for trading with other characters in the game. This skill allows you to buy goods cheaper and to sell them for more profit. "Guile" permits morally evil characters to sneak and steal more effectively.
Leveling your Skills
Play through the game by raiding caves, towns and killing creatures. Collect all of the green "orbs" that you earn using your combat skills and take them to the Hero's Guild. Purchase upgrades to your skills with the "orbs" following the pricing presented on the screen. Skills become more expensive as the level of you character increases.