After you defeat Brassius in Artazon, one of the recommended next destinations is East Province (Area One).
Explore the Area
If you go directly east from Artazon, you can find a TM037 Draining Kiss.
Go back to the eastern Pokémon Center of Artazon, then go northeast along the path. On the way, you can talk to a trainer to battle Salvador the Janitor, who has a level 17 Mareanie. You get 1564 Pokédollars for winning.
Farther along the path, you can talk to a trainer to battle Eleonor the Cook, who has a level 17 Slowpoke. You get 1700 Pokédollars for winning.
North of that, you find the East Province (Area One) Pokémon Center. The Pokémon League rep will give you a Loaded Dice if you defeat 5 trainers in this area.
Northeast of the Pokémon Center, on the way to the watchtower, you can talk to a trainer to battle Laia the Dragon Tamer, who has a level 20 Applin. You get 2400 Pokédollars for winning.
Northeast of that, there is a watchtower. There is a Gimmighoul on top that you can try to catch. If you want to reach the middle level of the watchtower, you will need to fall from above. The middle level has a TM113 Tailwind.
Southeast of the watchtower, you can talk to a trainer to battle Petra the Student, who has a level 21 Flittle and a level 21 Azumarill. You get 1092 Pokédollars for winning.
On the east side of the ledge north of the watchtower, you find a TM003 Fake Tears.
Northeast of the Pokémon Center, in a spot that overlooks a slope across the river to the north, you can talk to a trainer to battle Xavier the Student, who has a level 23 Kirlia, a level 23 Noibat, and a level 23 Zangoose. You get 3680 Pokédollars for winning.
If you go west from the Pokémon Center, you will see some flags for Team Star's Fire Base. West of those flags, you can go south into an alcove to find a TM050 Rain Dance.
When you go farther west, you get a call from Cassiopeia. Afterward, if you're ready, you can go southwest to the Fire Crew Base.
Northwestern East Province (Area One)
After you clear the base (or skip it), you can continue going northwest along the path through this area. When the path curves to the northeast, you can keep going northwest. You can talk to a trainer there to battle Valentin the Student, who has a level 19 Bramblin. You get 988 Pokédollars for winning.
Southwest of that, you can find a TM026 Poison Tail.
To the northeast, you can talk to a trainer near a tree to battle Abel the Worker, who has a level 22 Greedent. You get 2024 Pokédollars for winning.
Northwest of that, near the west wall where there is a cave entrance, you can talk to a trainer to battle Jorge the Student, who has a level 18 Komala. You get 1296 Pokédollars for winning.
North of that, you can talk to a trainer to battle Mercedes the Student, who has a level 18 Rellor. You get 1296 Pokédollars for winning.
Now you can go southeast to the main path and cross the bridge to reach East Province (Area Two).