If you go to the marshes on the right of town and head to the upper right there will be a dragon type cave. head through that and you'll end up in a grove of fairy types.
I decided to become a Steel Type gym leader since its my favorite type but I just can't find a riolu no matter where I look. Anyone have any tips on where I might be able to find one in the wild?
Once you reach rank 2 or 3 try checking back where ya got off the boat. though be ready for a fight.