To start fishing and cooking go to your spell book and teleport to the skilling area. Once there walk west into the building and trade with the Fisherman, make sure you have 25 gold pieces so you can buy all the fishing equipment.
[You must be registered and logged in to see this image.]Now to begin, you will be using your net to fish shrimps.
Shrimp - 1 fishing - 1 cooking - net fishing
[You must be registered and logged in to see this image.]Fishing a Shrimp will give you 476 experience in fishing and 621 in cooking.
Lobster - 40 fishing - 40 cooking - cage fishing
[You must be registered and logged in to see this image.]Fishing a Lobster will give you 1086 experience in fishing and 2159 in cooking.
Swordfish - 55 fishing - 55 cooking - harpoon fishing
[You must be registered and logged in to see this image.]Fishing a Swordfish will give you 1086 experience in fishing and 2159 in cooking.
Monkfish - 65 fishing - 65 cooking - net fishing - At this point you should go to your spell book, click on guildz, and go to the fishing guild. It is more compact and allows you to fish, cook, and bank alot faster then the normal skilling area.
[You must be registered and logged in to see this image.]Fishing a Monkfish will give you 2692 experience in fishing and 3161 in cooking.
Shark - 75 fishing - 75 cooking - harpoon fishing
[You must be registered and logged in to see this image.]Fishing a Shark will give you 3668 experience in fishing and 4633 in cooking.
Manta Ray - 90 fishing - 90 cooking - harpoon fishing
[You must be registered and logged in to see this image.]Fishing a Manta Ray will give you 4984 experience in fishing and 6747 in cooking.
Good Luck!