Fish Tutorial

First Step: Use your Fisher Outfit.
To fish, you must be using your Fisher Outfit. It isn't necessary buy, every character has one. If you look in you outfits, you will find it.
 
Second Step: Using the Fishing Rod.
You have two options: Click on the Fishing Rod (right or left mouse button) in the upper right angle of your client, according to the image below, or use the command 'Ctrl + Z'. It's up to you choosing what method you will use. After it, click somewhere in the water.
Third Step: Fishing the fish.
After you use the Fishing Rod in the water, wait until it starts bubble and pull the fish. (holding 'Ctrl + Z' again or clicking again in the Fishing Rod). Illustration:
 
 
All this baits can be found in NPC Guru.
 
Bait Pokémon Fish Nivel Price
No bait
Magikarp, Feebas
- -

Worm

Poliwag, Goldeen, Horsea, Remoraid
10 or more 10 cents
(0.10 dollar)

Seaweed

Tentacool, Staryu, Krabby, Shellder
25 or more 40 cents
(0.40 dollar)

Fish

Seel, Chinchou, Spheal
40 or more 80 cents
(0.80 dollar)

Shrimp

Poliwhril, Seadra, Seaking, Sealeo
50 or more 1 dollar

Kept

Corsola, Kingler, Starmie, Qwilfish
60 or more 5 dollars

Steak

Lanturn, Dewgong, Sealeo
70 or more 10 dollars

Misty's
Special Lure

Dratini, Dragonair, Dragonite
80 or more 20 dollars

Special Lure

Cloyster, Poliwrath, Politoed, Octillery
80 or more 30 dollars

Big Steak

Gyarados, Mantine, Kingdra, Tentacruel, Walrein
90 or more 60 dollars