Instructions
Capture every new Pokemon that you encounter on your journey. Don't wait until after you defeat the Pokemon League to start working on your Hoenn Pokedex. Always keep 20 to 30 Ultra balls with you whenever you travel to a new area.
Resist the urge to defeat a Legendary Pokemon like Groudon and Latios. If you defeat a Legendary Pokemon, you cannot catch it. Legendary Pokemon in "Pokemon Ruby" are difficult to obtain, yet you must catch them if you want to complete the Hoenn Pokedex. Save your game before you battle a Legendary Pokemon in case you defeat it or lose against it.
Trade with people who own "Pokemon Sapphire" and "Pokemon Emerald." Each third generation game has a version exclusive Pokemon. For example, you can only catch Kyogre, Lotad and Sableye in "Sapphire" and "Emerald." You must obtain Pokemon that are exclusive to "Sapphire" and "Emerald" to complete the Pokedex for "Ruby."
Evolve Pokemon like Ralts, Bagon and the three starters. There are certain Pokemon you can only get by evolving other Pokemon. For example, you can catch Trapinch easily in the wild. Yet you cannot catch Vibrava, its evolution, in the wild. You must evolve Trapinch to get Vibrava in your Pokedex.
Talk to every non-player character in "Pokemon Ruby." Some characters will offer you rare Pokemon in exchange for another Pokemon. A little girl in Pacifidlog Town will offer you a Corsola for a Bellossom.