Can someone tell me the easy way to beat the E4?

Raise your Pokemon to at least lv. 60

Use high level Pokemon that have supper effective attacks against the elite 4's Pokemon. A good Pokemon is Walrein. It's good against Drake's Pokemon. Walrein is also good against Glacia if it has an attack that's not ice- or water- type like body slam. Don't use dragon types against Drake though. Don't Let Walrein learn blizzard becuase of it's low PP and low accuracy. Instead teach it ice beam. And a grass type Pokemon is good against some of Wallace's Pokemon especially Whiscash. Don't use any normal type Pokemon in your party either.

Your groudon should have a fight move a fire move ,thunder, and earthquake, I've done the leugue lots of times with just my groudon and blaziken (blaziken wasn't much help though, even at level 65) my groudon was only level 68 but did the legue by itself it's moves were, thunder, brick break,overheat and eathquake. At least one of my moves was super effective against nearly every pokemon. Hope this helps. Dragonclaw

Well I can beat them in 3 Pokemon,the first Pokemon is blaziken on lv 100,use him for the 1st(double kick on all)and the 3rd(double kick again)elite people.
Second Pokemon use rayquaza on the 4th and last elite people(the 4th guy use dragon claw)and the last guy use dragon claw(make shore you are on lv 100 too.
and the last of all use salamence's crunch(let him learn)that is all u need to win
hope i helped.and good luck