It really depends on how far you are into the game, but the general answer is walking through grass, Surfing/fishing, and going through caves and forests to battle wild Pokemon and raise your Pokemon's level. Battling other trainers is also very effective because defeating their Pokemon usually gets your Pokemon more experience points than wild Pokemon.
If you already have a really high level Pokemon with a few good moves, you can make your lower level Pokemon hold exp. share, which will give it half of a battle's experience points. That means that you can go and battle the Elite Four twenty times in a row with your really powerful Pokemon and your lower level Pokemon will gain levels really quickly. You can also use rare candy, but they're hard to find unless you're playing Red/Blue and can do the infinite item glitch.
Hope this helped!
You can only get celebi in Pokemon XD by trading. The only way I know you can get a celebi to Pokemon XD except from events is the Pokemon Colosseum Bonus Disc.
you can't the only way to get him is on Pokemon firered and leafgreen or Pokemon colloseum
Pokemon xd in my opinion
yes you can. if you train the shadow Pokemon then just don't bring it to the relic and if you put shadow Pokemon in the purifie chamber, then take them out from your PC and not the purifie chamber.
You cannot snag a legit whismur in Pokemon XD, only trade to Pokemon XD from another game.
train... train...TRAIN...
Try out the orre colosseum or just train your pokemon.
The outskirt stand.
In Outskirt Stand
You can only get celebi in Pokemon XD by trading. The only way I know you can get a celebi to Pokemon XD except from events is the Pokemon Colosseum Bonus Disc.
There is no way to trade directly from Pokemon XD to Pokemon Coliseum. Instead trade from Pokemon XD to one of the GameBoy Advance versions of Pokemon, and then trade to Pokemon Coliseum.
You can't catch feraligatr in leafgreen you need to get a croconaw from Pokemon colosseum or get a totodile from emerald or Pokemon xd gale of darkness either way you must train both to get feraligatr.
Trade one from Pokemon colosseum or get a chikorita from either Pokemon emerald or Pokemon xd gale of darkness then train it to level 16.
Either get a Dratini from FireRed or LeafGreen and train it to level 55 or get the purified one from Pokemon XD: Gale of Darkness.
Yes but you Must train your shadow Pokemon really well.
Catch a rhyhorn then give it a lucky egg and then trade it to a friend and let them train it it will be rhydon before you know it. Other option: Take the shadow rhydon from Pokemon xd gale of darkness.
No unless you are realy good at the game!:)