The combat and battle system in Final Fantasy X is quite a bit different from the battle systems employed in previous games in the Final Fantasy series.
Combat in Final Fantasy X takes place in a turn-based manner. Each participant will have a turn in battle and the order is determined by whichever participant is the quickest (has the most Agility, specifically). There is no time-limit and you can take as long as you want with each turn that comes up. Check out the CTB Window section for more details:
Once their turn arrives they will have the option to select a command using the Command window. The commands will change depending on what abilities the character has unlocked on the Sphere Grid: White Magic, Black Magic, Special Abilities and Skill Abilities. Check out each of those sections using the links below for more information:
Skills
Skill Abilities are generally a physical attack that also includes an additional added affect (Mug, Dark Attack, Power Break, etc.)
Specials
Special Abilities are miscellaneous abilities that are typically specific to one character, such as Tidus’ Flee ability or Rikku’s Use ability.
White Magic (Wht Magic)
White Magic spells are those which have curative properties and will help your party members in battle (with the exception of Holy).
Black Magic (Blk Magic)
Black Magic spells are those that deal damage to enemy combatants and are used offensively.
During the battle, you may encounter a number of other one-off interactions including Trigger Commands, Overkills and Overdrives. Check out those sections of the guide by clicking on the links below for more information:
Trigger Commands
Special commands that become available during certain battles as you progress through the game.
Overkill
The impacts of “Overkilling” an enemy or a fiend and how to do it more effectively.
Overdrives
Using your characters Overdrives.
At the conclusion of the battle your party members will be awarded “Ability Points” or AP. They may also be rewarded with items which may include weapons, armor and items.