Route 20 (East)
After defeating Cheren, you can now access the second, eastern half of Route 20. Going down the steps after beating the Hiker will be a Preschooler ready to fight. Going a farther bit after that, Cheren and your Rival come to talk to you. Cheren tells you about the dark grass, which has higher leveled Pokémon and, sometimes, double battles. Your rival begins to train using this grass (although, with a level 8 starter without its same type move, that may not be a good idea.) Making your way northeastward leads you to the gate to Virbank City. However, before you enter, Cheren stops you again to give you Pecha Berries. These berries, when held, cure poison status without having to use an item. He explains that you may need them for the Poison type gym ahead. Going through the gate, the attendant will talk to you and give you some Great Balls for free, which is good, considering there will be some new Pokémon up ahead that you may want to catch.
Now in the city, there are a few things that need to be done before immediately going to the Gym. It would be wise to at least do some sort of training before hand.