use good Pokemon that's the only way
against the elite four infernape will do very good with its fire type moves but since the first gym is ground it is not so easy to beat it with a fire type. i beat the elite four 6 times with my infernape. the beat moves for it are fire blast and flame wheel
You beat all the gym leaders then the elite four
with skills :>)
he stays in the elite four as champion
See question "Is this a good team to beat the elite four"'s answer.
uuuhhhhh..... no..
no
One island.
The same you can do in Fire Red.Read my answer to that here:What_can_you_do_after_you_beat_the_elite_four_in_pokemon_fire_red
Nothing
You need to beat the elite four and get the national dex.
You can continue to challenge the Elite Four for money and Exp. Also you can get additional badges (stickers). Hall of Fame Sticker #1 Beat The Elite Four One Time Hall of Fame Sticker #2 Beat The Elite Four Fourty Times Hall of Fame Sticker #3 Beat The Elite Four One Hundred Times Hall of Fame Sticker #4 Beat The Elite Four Two Hundred Times