I don't know what Pokemon you have, but i beat the Elite four with just Swamper level 59 (grew to 62 when i was done with them) and Gardevoir level 50 (grew to 51 after) Swamper- ice beam, earthquake, blizzard, muddy water and Gardevoir- confusion, psychic, hypnosis, thunderbolt. Those were the only ones i raised through the game to Elite four. Hardest one was ludicolo on Wallace. Other than that, no problems.
how to beat Pokemon emerald
No
when you beat the elite four
Beat Elite Four.
Beat them and the champion
beat the elite four
what is your team?!?!?!
Beat the elite four
no
no
After you beat the elite four.
Beat all the gyms until you get to the elite four CRUSH THOSE ELITE FOUR PEOPLE and you will battle steven beat him and you beat the game