The game is split into three sections: the menu screen (where you control the Jobs, equipment, and magic), the overworld screen, and battle. Here's a brief synopsis of how to take advantage of the three. (If you're used to later Final Fantasies, i.e. FF4 and up, there are quite a few differences you'll have to endure.)
CONTROLS: For all three sections, the directional pad moves either the character or cursor around, A is the "yes" button (talks to people, searches, accepts commands) and B is the "no" button (cancels commands). They have specific purposes in each screen, however.
OVERWORLD/FIELD SCREEN: Fairly simple, use the directional controls to move around, press A to interact with things (talk, search, etc.) and press START to bring up the menu screen. Press Select to change the character shown on the screen (this doesn't do anything strategically except for Thieves, who can open certain doors when in front). Press B to bring up an item screen. If you ever have to use an item on something (it doesn't happen often) select it on this screen. If you select an item that has no use in the place you used it, it won't disappear, so don't worry!
BATTLES: Battles are turn-based: you select the commands for your characters to perform, then the battle automatically takes place, with each enemy and character performing exactly one action. Firstly, you can press left or right to see an arrow near the current character. If the character's in the back row, the arrow will point left; it'll point right if he's in the front row. Pressing A will switch rows (this takes up a turn). More about rows in the menu section.
Every character has the Fight (physical attack) and Item (use items) command; the other ones are dependent on the character's Job and are described in the Job section. Just a few common ones: "Defense" raises the character's defense for that turn, causing physical attacks to do half damage; "Run" attempts to run away from battle; "Magic" gives you a list of spells to use in battle. A character who tries to Run has zero defense. If he succeeds, the battle ends.
The Item command: Press left to see the items in the character's hands. You can even use some weapons as items during battle, but they won't disappear; see the Weapons section for more details. (You do not have to be equipped with the weapon to use it.) You can switch weapons in battle by selecting one with the A button, then selecting the other and pressing A. You cannot switch shields, however.
During battle, you or the enemy may be inflicted with different status properties. Following is a list of them:
OK, here goes the tough part. There are several parts to this screen, and I'll go through all of them.
ITEM: Use an item. To use an item, press A twice on it. If the item used is a spell, you will select the character to receive the spell (as long has he still has room). Characters can hold spells even if they can't use them. You can switch the positions of two items (or move an item to an empty space) if you press A on one item, then move the pointer to another item or an empty space. To throw an item out (not recommended), move it to the trash bin at the bottom of the screen.
MAGIC: Select a character to use the magic. There are three options here: Use, Swap, and Item. Selecting Use will use the magic selected. (There aren't too many spells you can use outside of battle; see the Magic section for more info.) Selecting Swap and selecting another character will change ALL magic spells between two characters. Selecting Item and selecting a spell will put that spell back into the inventory. Note that no character can carry more than three spells per level; there are 8 levels of magic. (You can have three L.1 spells and three L.2 spells at the same time, but not four L.1 spells.)
EQUIP: Change a character's equipment. There are five spots here: Two for weapons (or shields if that Job can equip them), one for head, one for body, one for arms. My experience is that it's much more useful to equip two weapons on strong physical fighters than to give him a shield. To remove an item, just put the cursor on it and press A. (You can't just swap positions of items in the inventory and equipped items, like later FF games. Sorry!) To equip an item on an empty space, select the space, press A, then select the desired item and press A. Items which can't be equipped by that Job have an X on their icon. You can see the changes the equipment makes on the character's attack and defense stats by looking at the numbers at the top of the screen. You can also select "Remove" to remove all equipment at once (as long as there's room).
Jamesbld36@aol.com reminded me that when facing only physical attacking enemies, it's a very good stragety to equip a Knight character with two shields. If all your other characters are already in critical condition, the Knight will block all the physical attacks on them, which will usually result in very low damage or a miss. He won't be very useful as an attacker though, so keep that in mind.
STATUS: There are several things to look at here. A character's level raises after gaining Experience points (EXP; gotten by winning battles). When the level raises, all stats also raise. You can see the character's current EXP and amount needed to raise the next level on this screen. As well, you can see the character's current (not total) MP here. (The only way to see total MP is to go to the Magic screen.) The character's Skill level is also shown here. Each character has a separate Skill Level for each Job. The Skill affects 3 things: attack power and amount of attacks, defense power and defense multiplier, and the amount of Capacity points needed to switch to that Job later, from a different Job. The higher Skill, the lower the amount of Capacity needed. There are several stats mentioned here; see Statistic Meanings for what they're all about.
ROW: Select a character to change his row from front to back. Back row characters' attack and defense stats are halved; as well, enemy attacks often miss them, and their attacks often miss the enemy. Put magic users in the back, leave physical fighters in the front.
JOB: Change the character's job. Before you can do this, you must go to the Equip screen and select the Remove option to remove all equipment. Then go to the Job screen and select the Job you wish to change to. The number beside the Job reflects the amount of Capacity points needed to change to that Job (Capacity points are dealt with in the Jobs section.)
Although I can't know for sure, I've made my best guess (with great help from Jim Shaheen) as to the meaning of the statistics in the Status menu. Note that whenever you see the Skill stat, subtract 1 from it; Skill is assumed to start at 0 (even though a Skill Level of 0 is impossible). The five stats on the left are innate and depend on the character's level and Job. The stats on the right are derived from the ones on the left.
Strength (Str): This stat affects the damage done by physical attacks. Attack power and multiplier is affected by this stat.
Agility (AGI): This stat affects speed. Attack and defense multiplier, as well as the order in which characters and enemies act during battle, is affected by this.
Vitality (VIT): This stat affects defense against physical attacks. Defense power and multiplier is affected by this stat.
Intelligence (INT): This stat affects Black Magic power.
Spirit (SPR): This stat affects White Magic power. (I believe that Call Magic power is an average of the two stats.)
Attack Power: This changes depending on what the character has in his two arms. This stat is the sum of the attack power of the two hands.
Attack Multiplier: This tells the maximum amount of times this character can hit during his turn. This is determined by his Level and Agility stat. (Agility/16 + Level/16) +1.
Hit %: Accuracy of physical attacks. Determined by Agility stat and Skill level: (Agility/4 + Skill/4) + weapon hit %. If you have two weapons this value is doubled.
Defense: His natural defense is half his Vitality stat (depending on the Job, it becomes higher or lower). If he's wearing armor, it adds to this stat.
Defense Multiplier: The defense stat may be multiplied by a maximum of this number during
battle for any one hit. This stat is found by Agility and Level:
(Agility/16 + Level/16) + 1 * number of shields equipped.
Evade %: The chance he has of evading physical attacks. This is determined by the Agility stat (Agility / 4).
Magic Defense: His defense against magical attacks. No Job has innate Magic Defense; only equipping armor can give this stat.
Magic Evade: The chances of magical attacks missing that character. Usually this is determined by the Job, but a few pieces of armor can raise it. Every spell has a special Magic Hit stat (you can't see it) which interacts with this stat. All-or-nothing spells like Kill, Break, and Death have much lower Magic Hit stats than regular attacks like Ice and Flare. This stat is determined by the Intellect and Spirit stats: (Intelligence + Spirit) / 2.
There is an invisible "magic multiplier" which is given by (Magic stat/16 + Level/16) + 1. The "Magic stat" is Spirit for Black Magic and Intelligence for White Magic; Call Magic is a mix of the two.
Here are some tips to get you through the game: