Fishing is one skill that counts as gathering but does not work like other gathering skills.
If you follow the blue lines down, you will find tha gathering skills. One of these is the Fisherman skill.
With it you can unlock the different tiers and tools.
If you follow the line down, you find the Fishing Specialist skill, that improoves your fishing skills further.
Both skills level if you catch or eat a fish.
The fishing rod is the essential tool for every good fisherman. Very important is the entry about Fishing Speed
The higher the value is, the faster the fishing bar will fill.
Higher quality also increases the fishing speed. So rerolling them at the repairstation sure is a good investment.
Also the tier of your rod limits your ability to catch some fish. In higher zones, you will need a better fishing rod, or your fishing line will rip.
On player and guild islands, as well out in the wild you will see school of fish.
Now you just need to hit it with your bobber.
You have to dismount and click and hold on the water.
You will see this bar:
The fuller the bar, the further you cast the hook.
Once the hook is in the water, you will have to wait a bit. You will here a sound when a fish bites.
Click and two bars will appear.
The top bar is your fishing line. Keep the bobber inside the green field. Holding the mouse button, will push him right, releasing it will make it slowly go right.
The bottom bar, shows you how far the fish is away from being cought. As long as you hold your mouse button, the fish will wander right. Once it reaches the arrow, it is cought.
The salad increases your fishing speed for 30 minutes and can be crafted with the seaweed you catch along the way.
Bait is usefull if there are no schools of fish. Usually you have to wait a long time for a fish to bite. The baits will reduce that time by a lot.
Ask your local farmer for worms and craft you some bait. It will open up some more spots for you for fishing.
Bait needs to be used from the inventory and lasts for 10 bites.