If youre still on the E4 (its been 2 hours) Can you post your team so we can judge their movesets? Anyways,
- Make sure all your pokemon are about the same level because the E4’s pokemon levels scale to the highest level Pokemon in your team
- BRING A TAUNT USER! Taunt shuts down their teams and will help you a lot, as Kayla uses Baton Pass, Eduard uses Sandstorm, Yuki uses Hail, and London uses Trick Room.
- I don’t know your team, but 2 really good Pokemon for them are Mega Haxorus and Scizor.
A Mega Haxorus with Dragon Dance, Dragonify, Earthquake, and Taunt/Outrage (Jolly Nature with 252 Attack and Speed EVs preferred) helped a lot with the E4,
and Technician Scizor with Bullet Punch, Swords Dance, Superpower, and Bug Bite (Adamant Nature with 252 Attack EVs preferred) can OHKO a lot of the Pokemon on the champions team if you manage to get 2 Swords Dance in and use the right moves, and the Pokemon you cant OHKO, you can deal with using your mold breaker Haxorus.
Also, credit for the Scizor strat goes to PeterHolmes74 (spoilers) here