Master Ball
Go to Lilycove City. Then, surf to Team Aqua's base. Keep walking around and you will see a room with four items. Try all the teleporters until you get to that room. The item on the top left is a Master Ball.
Starf Berry
Collect all Gold Frontier Symbols in the Battle Frontier. Then, talk to Scott at his house in the Battle Frontier.
Super Rod
The Super Rod is located near The Space Center. Go to the left of the Space Center. You should find a house where a fisherman is sitting on the chair. Talk to him and he will give you the Super Rod.
Watmel Berry
Go to the Berry Master's House and talk to his wife. Tell her "OVERWHELMING LATIAS".
Berry Fix
Press Down + Select + B at the screen with the glowing Rayquaza. You can now use the Berry Fix with Pokemon Ruby and Pokemon Sapphire.
Easy experience 1
Attach EXP Share. Put the Pokemon you want to gain experience in front of party, then fight someone. When the battle starts, switch it out for a better Pokemon. At the start of the game, train your starter in the grasses from Littleroot Town to where you fight your rival for your first time.
Easy experience 3
Fight all of the trainers that have a Poke thing next to their name.
Easy experience 4
Fight all of the gym leaders again.
Easy catches
Whenever you want to catch a wild Pokemon, you should first get one of your Pokemon to use moves such as Leer, Growl, and Flash. This will weaken your opponent. Attacking it might also help, but make sure that you do not defeat it. Also bring many Pokeballs with you.
How to beat the Elite Four
Take a normal level Pokemon with a one hit K.O. move and a lock on move. Also have a large number of Ethers and Max Potions. Just lock on and attack for and easy K.O.
Use the following Pokemon against the Elite Four
Electric: Raichu. Grass: Ludicolo. Fighting: Hariyama. Ice: Walrein. Water: Sharpedo. Ghost: Banette.
Elite Four easy
To make the Elite Four easy, tell the guy at the Weather Institute about the Drought to get Kyogre in the Sea Chamber. After the Groudon/Kyogyre/Raquaza incedent, go to the Sky Pillar, and catch him. Teach Kyogyre Thunder, for he has Drizzle. They are at Lv. 70, so you can easiy kick butt.
Get MewTwo
Restart the game and when Birch asks your name put your name a: MewTwo once you have done that you will go through all that stuff untill u get to birch where he needs ur help. When u get to select torchic and that choose torchic. run back to little root town and stand next to mum. save your game there. the run up to Oldale down then head up to May. before u reach May u will see a sign run into it then turn left run straight left into the tree the tap the d pad lightly just to turn around NOT WALK. when u get a battle with Mewtwo He should be lvl 25. Good Luck and go catch that mewtwo!!!
How to clone
1.You Must Unlock Battle Frontier First.2.Go To Battle Tower.3.Go To Computer 4.Deposit The Pokemon You Want To Clone5.Save Game.6.Withdraw The Pokemon.7. Talk To The Lady Closest To You. 8.Say Either Lvl.50 Or Open Lvl.Choose Two Pokemon.She Will Say To Save. Say Yes And Then No.Turn Off And Check Computer.
Duplicate pokemon
go to battle frontier then go to battle tower deposit the pokemon u want to duplicate and save. then withdraw the pokemon and enter the multi-link battle thing. (u dont need to enter the pokemon for battle)when it says SAVING, DONT TURN OFF THE POWER (turn off beforit finishes or else it deletes the game file)turn off. and there u go u have a duplicated pokemon!!