Well when you get to Pravoka, go west into the mountains then all the way north till you reach the ocean. The last 4 squares contain monsters you shouldn't be able to fight till later in the game. They'll be tough to beat but its worth it for the experience.
Here's a map I've typed.
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You can find every little fact on Materias, items, weapons, armors, accesories, enimies, locations, and easy ways to beat bosses. + all the secrets and hellpfull things like the code to get huge materia in rocket town or using an x-potion on the Gi ghost kills it.