One of the best strategies is Twin Pokémon. Even though they have double the chance of fainting altogether, they are almost an unstoppable team. Take, for example, my twin Vulpix. One female, one male. The male's nature is Lonely, and has a Hidden Ability, Snow Warning. That summons the move Hail, and puts the Female's Ability into effect. Her Ability is Snow Cloak, which increases the ability to avoid moves in Hail. The female's move set takes care of both lowering and increasing the in-battle stats. For example, Baby-Doll Eyes, Tail Whip, Etc. The male has a move, Confuse Ray, that confuses the target, a status condition. The female has a move, Hex, that does massive damage if the target is afflicted by a status condition. Considering they've both evolved into Ninetales, they have relatively amazing speed. Alolan Vulpix/Ninetales are relatively amazing examples for Twin Pokémon, so I hope this was helpful.