Final Fantasy

Port-specific

• NES: The RNG (random number generator) is not really random. If you power cycle (save, turn the machine off, then back on), you can predict very specifically what monsters you'll see when. A good example of this is when you are on your ship. The first battle will always be against a Kyzoku. When you get the ship, this is one of the better sources of GP at the time, excluding the Peninsula of Power, of course.
• PS: The ship mini-game, 15 tile puzzle, can be used to get loads of Gil in a very short amount of time. Every time you break the #1 record, you get 10,000 gil, a potion, an antidote, and a gold needle. Also in this version, all four fiends (plot and final dungeon) and Chaos have double HP. The game also has several bug fixes from the original, including elemental attributes on weapons, the spell "Steel," and (unfortunately) running away from battles. And finally, the addition of memosave allows you to skip all random battles entirely. Simply walk as far as you safely want, memosave, soft reset (R1, R2, L1, L2, Start, Select) and resume playing. The memosave lasts as long as the Playstation's ram, so once you hit reset or power, it's gone.
• GBA: Dawn of Souls is the easy version that came with Origins. You gain experience much quicker, bosses have altered HP (Garland is doubled, for instance) that don't follow any formula, so consult a bestiary guide. Instead of memosave, you can save anywhere you wish, which also allows you to skip all random battles entirely like Origins does. The game also replaces the old "charge" MP system with a "normal" one. This allows for much freer reign on spell casting, and generally makes the mages insanely powerful.
• PSP: The 20th Anniversary Edition is Origins + Dawn of Souls + one new dungeon. It is also the easy version of the game, following the same experience tables Dawn of Souls and Origins' easy mode used. However, battles flow slightly slower than the other two enhanced ports.

General strategies

• Haste greatly increases accuracy in battle, obvious uses are against bosses or powerful enemies.
• Steel and Saber (TMPR and SABR in the NES version respectively, but they don't work) increase attack power in battles. Also useful against bosses or powerful enemies.
• All buffs stack with themselves. So if you cast Blink a few times, you'll eventually max out your evade. The same applies to all buffing spells, with Haste being the exception.