How to beat the Elite Four - Guide for Pokemon: FireRed

HOW TO BEAT THE POKEMON LEAGUE
When you fight the pokemon league, make sure you have a fire type, water type, 
electric type, a psychic type and an ice type attack. And make sure their strong. 
Also, bring lots of Full Restore, Full Heals, Max Potions, and Revives. 
Battle 1: Lorlei
1st—Dewgong lvl.52—use electric or grass
CLoyster lvl.51—same as above ^
SLowbro lvl.51—use electric, grass, ghost, dark, or bug
Jynx lvl.54—use fire, ghost, dark, or bug
Lapras lvl.54—use same strategy as Dewgong

Battle 2: Bruno
1st—Onix lvl.51—use grass or water
Hitmonchan lvl.52—use psychic or flying
Hitmonlee lvl.52—same as above^
Onix lvl.54—use grass or water
Machamp lvl.56—use psychic or flying

Battle 3: Agatha
1st—Gengar lvl.54—use psychic
GOlbat lvl.54—use psychic, ice, rock, or electric
Haunter lvl.53—use psychic
Arbok lvl.56—use psychic or ground
Gengar lvl.58—use psychic

Battle 4: Lance
1st—Gyrados lvl.56—use electric
Dragonair lvl.54—use ice
Dragonair lvl.54—use ice
Aerodactyl lvl.58—use ice, water, or electric
Dragonite lvl.60—use ice

Rival Battle
Will always have:
1st—Pidgeot lvl.59—use electric
Rhydon lvl.59—use water, grass, or ice
Alakazam lvl.57—use dark or ghost
If you chose Bulbasaur:
Exeggutor lvl.59—use fire, ghost, dark, or ice
Gyrados lvl.61—use electric
Charizard lvl.63—use water, rock, or electric
If you chose Charmander:
Arcanine lvl.59—use water, ground, or rock
Exeggutor lvl.61—use fire, ghost, dark, or ice
Blastoise lvl.63—use electric or grass
If you chose Squirtle:
Gyrados lvl.59—use electric
Arcanine lvl.61—use water, ground, or rock
Venusaur lvl.63—use fire, psychic, flying, or ice

WHEN YOU CHALLENGE THE ELITE FOUR THE SECOND TIME
In previous pokemon games, after you beat the elite four, you can just keep coming 
back and leveling up your pokemon. But in FireRed and LeafGreen, when you come back 
to try beating the Elite Four a second time, they will have changed their pokemon 
and they will have leveled up at least 10 levels.
Lorlei
1st—Dewgong lvl.64—use electric or grass
Piloswine lvl.63—use fire or grass
Cloyster lvl.63—use electric or grass
Lapras lvl.66—use electric or grass
Jynx lvl.66—use fire, ghost, or dark

Bruno
Steelix lvl.65—use fire
Hitmonchan lvl.65—use psychic or flying
Steelix lvl.66-use fire
Hitmonlee lvl.65—use psychic or flying
Machamp lvl.70-use psychic or flying

Agatha
Gengar lvl.68—use psychic
Golbat lvl.66—use psychic, rock, ice, or electric
Gengar lvl.70—use psychic
Arbok lvl.68—use ground or psychic
Misdreavus lvl.65—???(since Misdreavus is only a ghost type, hit it with any type of 
special attack)

Lance
Gyrados lvl.68—use electric
Aerodactyl lvl.70—use ice, electric, or water
Dragonite lvl.72—use ice
Kingdra lvl.65—???(since Kingdra is a water/dragon element, grass, ice, and electric 
type moves only do normal damage)
Dragonite lvl.66—use ice

Rival Battle
Heracross lvl.72—use fire or flying
Charizard/Blastoise/Venusaur lvl.75—use electric or water for Charizard, electric or 
grass for Blastoise, and ice, psychic, fire, or flying for Venusaur
Alakazam lvl.73—use ghost or dark
Gyrados/Exeggutor/Arcanine lvl.73—use electric or rock for Gyrados, fire, flying, 
dark or ghost for Exeggutor, and water, ground, or rock for Arcanine
Tyranitar lvl.72—use ice or water
Exeggutor/Arcanine/Gyrados lvl.61 (around)—use fire, flying, dark or ghost for 
Exeggutor, water, ground, or rock for Arcanine, and electric or rock for Gyrados.