Now you're in Pewter City. Explore the city and buy things and then go to the city gym. First you will face at least 1 Junior Trainer and then Brock. Junior Tranier Has: Sandshrew and Diglett
BROCK Has: Geodude and Onix
Best Option: Use Butterfree
You'll Get: BoulderBadge and TM 34(Bide)
Technique: Cut (See HM's and TM's section)
ROUTE 3
Make sure you're well prepared to fight on this route. There is a total of 8 trainers. (Be sure to avoid the ones you can) Most are bug catchers. Before you enter Mt. Moon go to the Poké Center and heal your Pokémon, then proceed. There is also a man who will sell you Magicarp if you want it. (You can get lots of them free later so I wouldn't unless you want Gyrados sooner.)
Mt. MOON
There are many trainers in here. Also look for a Potion, Escape rope, HP Up, TM 12, and 2 Moon Stones. At the end of the cave you will fight two trainers. Jesse and James have: Meowth, Ekans, and Koffing.
ROUTE 4:
Nothing much is here. There is a TM 04 whcih contains Whirlwind. Be careful not to jump over the last ledge unless you want to go back for something.