After a friendly battle with Captain Ilima, you can head north to Route 2 on your way to Verdant Cavern.
Go up Route 2 and you will encounter Beauty Krystal. She has a level 9 Gastly. It's weak to Ghost, Psychic, and Dark attacks. You get 288 Pokédollars for winning.
The man standing near the grass will tell you about shaking grass. If you go into the grass, the pokémon will rush toward you.
From there, you can go north up the ramp. If you go southeast from the top of the ramp, you will reach the Hau'oli Cemetery.
In the cemetery, check behind the bottom-left grave to get a Paralyze Heal.
In the center of the cemetery, you can battle Pokémon Breeder Ikue. She has a level 9 Pikachu. You get 360 Pokédollars for winning.
Talk to the man at the bottom right to battle Gentleman Stanley. He has a level 9 Makuhita. You get 1800 Pokédollars for winning.
Go through the grass at the bottom-right of the graveyard and follow the path to get TM100 Confide.
Check in front of an upper-left grave to get a Super Potion.
Check behind an upper-right grave to get a Big Mushroom.
Talk to the guy in the upper part of the graveyard to battle Office Worker Jeremy. He has a level 9 Diglett. You get 360 Pokédollars for winning.
Back to Route 2
After you are done in the Cemetery, go back to Route 2. Go up the hill until you see a girl on the left and a house on the right. If you go southwest here and go through some grass, you find a Heal Ball.
Go back up the hill. There is a motel on the left. If you go into the motel room and talk to the guy sitting at the table, he gives you 2 Nest Balls.
Go to the upper-left corner of the motel parking lot to find a Super Potion.
If you go north past the motel, you will battle Preschooler Kaleb, who has a level 8 Spearow. You get 96 Pokédollars for winning.
Keep going north from there and you will see a Delibird in the path. Then go into the Berry Fields across from the Delibird. After a cut scene, you have to battle a Team Skull Grunt. He has a level 10 Drowzee. You get 320 Pokédollars for winning.
Afterward, the man will give you an Oran Berry. Check on the berries in front of the tree behind the man and you will get a few more berries.
Go to the right and go into the house. Talk to one of the Delibirds in the bottom-right corner to get a Revive.
Go around the back of the house to get Silver Powder.
Outside, go south into the berry field area. Check on the basket to the right to get a Repel. Go to the bottom-left corner of the area to get a Big Mushroom. Then go around to the top of the tools above where you got the Big Mushroom, and check on the flower pots to get a Paralyze Heal.
If you talk to the man in the berry fields again, he will ask if you want to become a Berry Master. Say yes and he will ask for a certain type of berry. If you have it, talk to him again to get another berry.
Leave the Berry Fields and go north. Follow the path and you can battle Backpacker Ashley. She has a level 10 Cottonee. You get 240 Pokédollars for winning.
If you go to the southern part of the path, you can battle Lass Isabella. She has a level 9 Misdreavus. You get 216 Pokédollars for winning.
Behind Lass Isabella, there is a Super Potion.
If you go along the northern part of the path, you can go through the fence and go northeast along the cliff to find a Revive next to the wall.
Nearby, you can battle Pokémon Breeder Jay, who has a level 10 Butterfree. You get 400 Pokédollars for winning.
On the other side of the fence, you can battle Preschooler Malia. She has a level 9 Cutiefly. You get 108 Pokédollars for winning.
Route 2 Pokémon Center
Go farther along the path and you find Hau outside of the Route 2 Pokémon Center. You go with Hau, and he gives you three Revives.
You can talk to a girl in this Pokémon Center to trade a Spearow for a Machop. Spearow can be found in the grass near this Pokémon Center, or in Route 3 (but the path to Route 3 is blocked right now).
There is also a girl in the Pokémon Center who will pay you if you catch Cutiefly and show her your Pokédex entry of Cutiefly. Cutiefly can also be found in the grass near this Pokémon Center, or in Route 3 (but the path to Route 3 is blocked right now).
Outside, you can go northeast of the Pokémon Center to find berries under a tree. Check on them to get some berries.
When you are ready, go across from the Pokémon Center and approach Captain Ilima, who is standing outside Verdant Cavern. He will ask if you are ready to start the trial. You won't be able to leave until you complete it. If you are ready, say Yes.