I've leveled cooking to 375 and fishing to 350. Max cooking is not only personally useful but great for at least one person to have in a guild. Rogues and hunters especially send me stuff to cook for +agility. Fishing is a must for golden fishsticks, which give a buff for healing, and broiled bloodfin, which can give a quick resistance boost.

I find fishing relaxing - with Fishing Buddy installed, it is easy to chat. A good way to work on your fishing is anytime you are waiting around for a group - who doesnt wait at least 10 minutes for an instance to start? Find the nearest water and cast away. Always carry some +100 lures (ask your alchemist to make them for you) to guarantee the maximum catch.

High-level fishing also enables you to fish up motes of water and cook the top recipes in the game (fisherman's feast, spicy crawdad, hot buttered trout). And of course, at 70 you can do all the daily fishing quests for gold and goodies.

At lower levels of fishing, if you hit pools along the coasts, such as STV and Feralas, you will fish up tons of leather, cloth, and greens.