First, let's head into the house south-west of the entrance. Inside, you'll find the mother of the main character from Black/White. She'll greet and talk with you. She'll also offer to heal your Pokemon whenever you speak with her, so keep this in mind.
After you're done speaking with her, head upstairs and grab the King's Rock next to the bed. Once you have it, exit the house. When you're back outside, turn your Dowsing MCHN on and use it to find the Zinc to your west. Then, take the path south and enter the eastern of the two houses.
Talk to the bald man inside. He's Cheren's father and will give you some Berry Juice . Sweet! Once you get it, head back outside. Now head to the building in the north-west part of town. Yep, it's Juniper's lab! Head inside. Here you'll find Professor Juniper herself.
If you speak with her when you've seen all 297 of the Pokemon in the Unova Pokedex (not counting event Pokemon such as Victini), she will give you a License so you can visit the Nature Preserve from Mistralton City's Cargo Service.
When you speak with her after you've caught all 297 Pokemon in the Unova Pokedex, she'll hand you the Oval Charm , which ups the chance of finding eggs.
Then once you've caught all of the Pokemon in the National Pokedex (excluding event Pokemon), she'll present you with the Shiny Charm --this precious item boosts the chance of finding Shiny Pokemon.
It might seem like a lot of effort, but it's definitely worth it for the hardcore Pokemon Trainers out there. Also here is the Professor's hubby, Cedric. Speak with him and he'll give you the Super Rod . Hell yes! You can now fish at any body of water all around Unova! How awesome!
Once you're done, head back outside. That's all there is to do in Nuvema Town actually, so head back into Route 1 and continue on where you left. That's if you're actually following the walkthrough exactly.