Pokemon: Pidgey, Oddish, Bellsprout

In Cerulean, look for the house that was onced blocked by a police officer. She's moved to the side, allowing you to enter. Go inside and out the back way. You'll fight a Rocket, not too hard and you'll receive TM28. Continue around the back and you'll soon find yourself outside the city walls. Continue on down. If you head down the hills, you'll encounter a house. Inside, a man will take care of 1 Pokemon. While you walk around, it gains free EXP. The lower-right of this route contains the entrance to the underground path. Find the house and follow the path. A girl inside will give you a Machoke if you give her a Cubone. You probably don't one of those yet.

At the other end of the underground path you'll wind up in Route 6.

Pokemon: Pidgey, Pidgeotto, Rattata, Jigglypuff, Abra

A few trainers here that dish out good EXP. Be sure to snag any Pokemon don't have. Go south and you'll see Vermillion City.

Lots of things to do here. Go to the Pokemon Center and heal. Then locate the Pokemart and stock up on items. To the far left of the Mart is the Pokemon Fan Club. Inside, a man will give you the Bike Voucher.