Route 204 to Floaroma

When you step out of the cave, you see a boy standing there. He asks, rhetorically, if you are raising many types of Pokemon. He suggests that you keep a good variety of Pokemon types to avoid getting stuck against types of Pokemon that are strong against yours.

Go up the stairs and to the right, a trainer Armoa Lady Taylor, who has a lvl 9 Budew, and a Cherubi, lvl 11. The Budew will just attack you with Leech Seed, which will drain your health and give it to Taylor's Pokemon. The Cherubi will boost itself with Growth than attack with Tackle.

Just beyond her, you will see an Item Ball, which has an Awakening. From there, head up through the grass, toward the pacing person on the far side. This is a trainer, Bug Catcher Brandon, who has Wurmple, lvl. 10, and Kricketot, lvl. 11. They are fairly easy to beat, but the Kricketot is tricky to deal with as it has Bide, which will do damage based on damage it takes over two turns. It will use it frequently, so take some time to lower its stats then attack, trying to take it down quickly.

Head a little up, then to the left to progress. There are a pair of girls who will challenge you, take a moment and get two Pokemon ready to fight them, Twins Liv and Liz. They both have Pachirisus, lvl. 11. THey will attack aggressively, so having either Pokemon who are strong against them or Pokemon that are well healed will help you take them down. Eventually, one may use Bide, so keep on alert for it. When it does, hold off on attacking to either heal your Pokemon or debuff theirs.

After that, keep going to the left a bit more, through the fencing to find an item ball holding TM 09, Bullet Seed. Head back to the right a bit then up between the fences near the twins. Just through there is Floaroma.