Avoid using Fire, Rock, Steel, Grass, Fighting-type moves. These are super effective against Garchomp, and Garchomp can use them on your Pokémon.
Bring Pokémon that resist Ground and Dragon-type moves.
* Gliscor & Hippowdon are especially excellent choices, as they also deal good damage to Garchomp.
* Other good choices include Latias, Latios, Skarmory, and Togekiss.
Keep your Pokémon healthy. Garchomp can easily knock out your Pokémon if they are not at full health. Use healing items and moves like Heal Pulse and Soft-Boiled to keep your team healthy.
Bring a Pokémon with a move that can lower Garchomp's Defense. This will make it easier for your Pokémon to deal damage to Garchomp. Some good options include Sword Dance, Dragon Dance, and Hone Claws.
Be prepared for Garchomp's Mega Evolution. If Garchomp Mega Evolves, its stats will increase dramatically, and it will become even more challenging to defeat. Make sure to bring Pokémon strong enough to take on Mega Garchomp.
Use strategy. Garchomp is a powerful Pokémon, but it is not unbeatable. By following these tips, you can increase your chances of defeating it.