You start out in Pallet Town, There you will get your first Pokémon from Prof. Oak. You get him to bring you to his laboratory, you must first go North into the tall grass, you will hear someone say, "Don't go in there!" It's Prof. Oak, He'll take you to his lab and you'll have the choice of three Pokémon, Charmander the fire Pokémon, Squirtle the water pokémon, or Bulbasaur the grass Pokémon. If you pick any one of these Pokémon, Gary will pick the Elementally superior. Water beats Fire, Grass beat Water, Fire beats Grass. Beginners should pick Bulbasaur, he seems to win the most battles and beat the most trainers, Medimum style trainers should pick Squirtle, and Experienced trainers should pick Charmander. Gary will challenge you right after that, hes not too hard to beat, just keep attacking and he'll go down (Your Pokémon will grow a level).After that you will have to go North to Viridian City.
Road to Viridian City
Along the road the first guy you see will give you a potion. Also you cannot catch Pokémon right now so just defeat the Pidgeys and Rattatas for exp. points.
Once you reach Viridian City you should go to the Pokécenter and heal your Pokémon. Go to the Mart and the clerk will hand a parcel to you to deliver to Prof. Oak, You can jump over the little barriers, you will save time and also you'll encounter less battles. Upon delivery, Prof. Oak will hand you the PokéDex Gary will note to get a map from his sister (you can too).You won't have to battle Gary this time so get the map and head back to Viridian. There you should buy Pokéballs, Potions are not needed really because you are close to a pokécenter. In the area, Pidgeys and Rattatas are the only Pokemon found.(For exp. points, you can head West and battle Gary, but your Pokemon should be level 12 or above).Now Head North to Viridian Forest.
You cannot pick up the items to the right just yet, but you will go back later in the game. In the forest there are 3 trainers, they use bugs so if you chose Charmander this should be REALLY easy, if you picked Squirtle or Bulbasaur then it will still be easy but not as easy as Charmander. Go West from the beginning and you can pick up a Pokéball, but you do have to walk through the grass. Go Northeast of the beginning to fight a trainer(You have to fight this one), His Pokemon are: Weedle level 6 (Bulbasaur is immune to the poison in poison sting),and Caterpie level 6. From there go North along the road (The next trainer is optional) Keep going North and you'll find a Antidote. Go along the road and you'll find a split towards the end, go South and you'll find another item. A certain Pokemon you should look for is Pikachu, Although Pikachu is here, he is weak and doesn't have many moves. But he is effective against Misty. Once out of the forest, You'll have to go to Pewter City.
In Pewter city you must fight Brock. If you don't you cannot proceed to Mt. Moon. Brock's Pokémon are Geodude level 12, and Onix level. 14. Brock's Pokémon are easily beaten by Squirtle or Bulbasaur, Charmander's just out of luck and will have to make it with what he has (Evolving a Kakuna and/or a Metapod is a good choice if you're using Charmander).The BOULDER BADGE increases you Pokémon's power a bit, also flash can now be used(Badge moves such as FLASH, CUT, FLY, STRENGTH, and SURF can only be used when a HM is equipped to a pokémon.)Get some supplies and head to Mt. Moon. You'll want to get some potions, an Escape Rope or two, and some more Pokéballs if you need them.
Mt. Moon is long. Once inside you can find various items, and many people to battle. Team Rockets first appearance comes in here, They're easy so don't worry. At the end you'll fight a Super Nerd, After you beat him you'll get the choice of two fossils, The Helix fossil or the Dome fossil. Which one you pick matters on what Pokemon you'll get later, Helix: Omanyte, Dome: Kabuto. You can't get these Pokemon until later in the game so store then in your PC as soon as you get to Cerulean City. You should get a Clefairy and a Jigglypuff while you're there(Average level 6-10).
Did you get a Pikachu in Viridian Forest? If you did and you own a Squirtle or a Charmander that'll help win if you boosted his stats to about level 10 or above, If you have Bulbasaur it'll still be easy so don't worry. You only HAVE to fight one other trainer, the one near the beginning of the gym is optional. Misty is difficult if you chose Charmander. Her Pokémon are Staryu and Starmie. I don't know what level they're at. If you win you'll receive the CASCADE BADGE, it allows ALL Pokemon up to level 30 to obey, also lets you use CUT. If you go to the 1st house on the Northwest side of the city, you can go into the backyard and find a Rare Candy, You'll have to search a bit but its in the middle of the two rows going horizontally(Rows meaning spaces North to South in space).Bikes are too expensive right now (But you'll get one soon enough).
Road to Bill's house/Bill's house
From Cerulean City, head North and fight Gary, go across the bridge and fight all the trainers there. Go into the grass to the West and get a grass Pokémon(Depending on version) and get an Abra also. To catch an Abra, just throw a Pokéball at it (its not a guaranteed catch but its the best way right now).Go East to get to Bill's house, there are lots of trainers in the way so you may have to go to the Pokécenter in Cerulean. Once you get to Bill's house you'll see a Pokémon but no Bill. Talk to the Pokémon and do as he asks. After that Bill gives you a ticket to the S. S. Anne. Go back to Cerulean and you'll see that the Police man \ woman?? has moved so you can get into the house. You'll find a ROCKET in the back, beat him and get TM #28 (DIG) go back in the house and the guy doesn't care anymore so just keep it! Head South and you'll find a tunnel, go through it and you'll end up in Vermilion City (In the tunnel there is a Full Restore but You'll have to search for it because its invisible, like the Rare Candy).
In Vermilion you have a few things to do:
1.Get the Old Rod from the fishing guru (Next to the Pokécenter),
2.Beat Lt. Surge and get the Thunder Badge,
3.Get the Bike Voucher from the Pokémon Fan club president,
4.And also get on the S .S. Anne.
First thing first though, Lt. Surge is an electric type Pokémon gym leader so use a Diglett from the cave to the East. The Diglett should be almost totally immune to the attacks of the electric Pokémon. To fight Lt. Surge you have to search the trash cans for a switch (It's random), and the a neighboring can for the second switch. Lt. Surge's Pokémon are Pikachu and Raichu, I don't know their levels though. the THUNDER BADGE speeds up your pokémon a bit and lets you use FLY. Get the Bicycle with the Bike Voucher and use that, The Bike speeds your journey up A LOT.
On the S. S. Anne there are many good trainers so make sure your Pokémon's levels are high and look for the Capt. Because the Capt. gives you the CUT HM. If you go into the kitchen you will find a Great Ball in one of the trash cans. Try to search all the rooms because there some great things in there. From here you should go through the Digletts cave.
Not much here, Ride your bike through and catch a Diglett. Once through the cave you'll see a house. There you can get the Flash HM and the items you couldnt before (with CUT equipped onto a Pokemon).Go back and East through the mini-maze.
Just stay on the middle track and go North on the last turn if you're going on a track where at the beginning there was a man near a sign your going the wrong way, you should see a track going left, a man, and another man but not in the same place. Go Northeast and you should be on a direct track where a Jr. Trainer(Female) is waiting for you, fight her and go East.
Just before the Rock Tunnel you should be at a river with a nearby field and a little barricade you can jump over. Go South to the Pokécenter and heal your Pokémon, now go North and catch a Voltorb. Equip Flash on it and proceed into the cave. Go through the cave, its semi-direct not TOO confusing.
Once out of the cave you should be just North of Lavender Town.You don't have to fight the trainers so just go to the Pokécenter and heal up. Now Proceed West and through the tunnel. (You'll have to fight at least 1 trainer) Now you should end up in Celadon City.
You have a number of things to do here in Celadon:
1.Defeat Erika and get the Rainbow Badge,
2.Get the Silph scope,
4.Get the Coin Box for the Game Corner,
5.Get a Fresh Water From the Mart (top floor) and give it to the road guard. Erika isnt too hard to beat, Just Use a fire or bird Pokemon thats around the same level as her Pokémon. You're gonna have to battle at least 3 trainers. You MUST come with a Pokemon with CUT equipped. The easiest way to go is on the right and hug the left side. Erika's Pokémon: Victreebel lvl29, Tangela lvl 24,Vineplume lvl 29. The RAINBOW BADGE make Pokémon up to level 50 obey, and you can use STRENGTH. Next your gonna have to go into the Game Corner, fight the guy who is guarding the poster and press the switch behind it. Go in the door and go down another flight of stairs. There will be a number of puzzles to solve and Rockets to fight. One guy at the bottom should drop a lift key. Now take the lift and go to the bottom floor, You'll have to fight two Rockets and then fight Giovanni, Now after you've fought Giovanni, he should drop the Silph scope, the one for the ghosts in the Poketower. Now go back to Lavender Town.
Lavander Town 2
Nothing has changed, just go to the Poketower and fight the ghosts. When you fight the ghosts the silph scope works automatically. Once you've made it to the 2nd to the top floor a ghost will fight you (pre-programmed battle)This ghost is Marowak and you cannot catch her. Use a water Pokémon and it should be easy.Beat all the Rockets on the top floor and you'll recieve the Pokeflute from an old man. Now you should be able to wake up the sleeping Pokemon to the South (Snorlax) Also make sure to capture him because there are only 2 Snorlaxes in the entire game.
Once you've beaten the ghosts in the Poketower you should go to Saffron City to Battle Sabrina. But First your gonna have to save the town from Team Rocket. By now, the guy in front of the Silph co. building has fallen asleep (He'll be off to the side and won't stop you). Once you go inside its a maze, First you must fight many people (this includes scientists) and find the Key Card, This will allow you to get into all the locked areas. Next you must find a portal that leads you to Gary (You'll have to battle him) once you defeat Gary, A nearby man will give you Lapras. Go through the other portal and defeat Giovanni once again. He is easy with Squirtle or Bulbasaur, since he uses ground Pokemon Water and Grass Pokémon are effective. You'll get the Master Ball from the President of Silph co. SAVE IT! Its VERY important! Store it on your PC. Now Team Rocket has left town so you can now Go and defeat Sabrina.She uses Psychic Pokémon and isn't too difficult. Still be careful, you don't have to fight any trainer besides Sabrina, just go into the opposite portal unless you want Exp. points, You'll know when you reach her. Sabrina's Pokemon are Kadabra and other Pokémon I don't remember. Her Pokemon should be about level 30 or above. You get the MARSH BADGE for beating her, Pokémon up to lvl 70 will obey you. Next to Sabrina's Gym is the Fighting Dojo. This Gym is fighting Pokemon only, and if you beat all the trainers you get the choice of Hitmonlee or Hitmonchan. Hitmonlee is a Kicking based Pokémon and Hitmonchan is a Punching based Pokémon. Now you should head to where you met Snorlax (South of Lavender Town) along route 12 to Fuschia City.