Get Mystery Gift:
Go to any Poke'Mart. Then, go in front of the questionare, and enter "LINK TOGETHER WITH ALL" Then, once you save, you can now get access to Mystery Gift.
Get Groudon and Kyogre:
It's simple but difficult. Beat the game once. Then go to the weather station, talk to the weather man upstairs, and he will tell you where they are. If he says route 116, go to route 116 or if he says route 125, go to route 125. You must be calm in order to get these pokemon. Kyogre or Groudon might be in a cave, under the ocean. When you are about to battle them, lower their energy to red and paralyze them, or just make them go to sleep, then capture them with an ultra ball. Do not poison them or they will go away.
Get the National Pokedex:
After you beat The Elite 4, Professor Birch will come and give to you when you leave your house.
Get Latias or Latios:
After you beat The Elite 4, go to your house and watch TV downstairs. When your mom asks you what color the Pokemon is, reply BLUE for Latios or RED for Latias.
Get GSC Pokemon at The Safari Zone:
After you beat The Elite 4, go to The Upgraded Safari Zone, where you can catch GSC Pokemon such as Miltank, Aipom, Stantler, etc.
Get Johto Starters:
Once your pokedex is toally filled, talk to Professor Birch.
Infinite Steps in Safari Zone:
When you pay 500 to go to Safari Zone, get to a grassy patch. Instead of walking, lightly tap the Directional buttons in 90 degree angles and you won't waste any steps and may still catch Pokemon.
When you get your frontier ticket from your dad go to Lilycove City to criuse to the battle frontier [you can't fly there until you get there first] once you get there look at your frontier pass [press start and go to your name for your pass] look at the map for the battle frontier look for the battle tower go there. Then go to the PC and deposit the pokemon you want to multiply. Put them in any box to save then take them back out again the talk to the LINK MULTI lady when she asks you to save say yes then when it says SAVING DON'T TURN POWER OFF....... turn it off and turn it back on again and the pokemon you multiplied should be with your party pokemon and in the box you choose to put them in.
Get a master ball from Lilycove:
Talk to the lady in the counter and she will give you a ID.If all the numbers match with any of your pokemon's ID numbers then you will get a master ball.
Thanks to Revolution readers AmyEvil, Steve Bruckheimer, Judiah215, Tool, Robert, 165swissbeatz , shams and clyde!