Spelljammer: Pirates of Realmspace/Honest merchant

Dock in a port
Dock your galleon and enter town. First of all, go to the government building and pay your taxes.

Inquire about work in pubs
Go to the local pub and inquire about work.

If you are asked to destroy another ship, refuse: you are currently too weak to fight.

If you are asked to transport people or goods to another port, accept it: it is the best way to make quick money. Usually, the reward is between 1000 and 9000 gold pieces.

When you reach the destination port, go to the government building (not the pub) and collect the reward. You will also earn experience points, and eventually gain some levels (just the captain, not the crew).

Pick up cargo at the warehouses
The second method to make money involves the warehouses, especially if you had to refuse the job at the pub.

Go to the local warehouse and select Pick up cargo: you will be asked to transport a stock to a specific port, and the reward upon job completion will be usually 1000 GP. Note that the port taxes in Clive's Den are more than the reward: decline picking up cargo bound to that destination, unless you got another job in a pub with the same destination.

Note too that prices for goods do not vary from port to port, so you cannot make a profit through buying and selling cargo.

Ports
As soon as you complete a job, go to either the pub or the warehouse in the same port, and get a new contract.

As per the table above, the ports with the lowest taxes are Hisssta and Mingabwe. If at any time you are left without job, head for one of them.

Encounters
Avoid combat during this phase of the game.

Whenever an encounter starts, if the ship is hostile it will start shooting from the distance; if it is a friendly merchant, it will hail you (feel free to hail first); if you receive no response at all, probably the ship is haunted by the undead.

When a ship hails you or responds to you hail, you can talk and learn stories (but sometimes they are sailor's lies), and you can trade goods. Be careful:

If a ship is hostile, turn your back and shift to "stern view" (press F9). Flee as fast as you can, and dodge its projectiles. Neogi mindspiders and deathspiders are always hostile.

Text transcript (spoilers)
There are 24 different jobs that require to transport passengers or, occasionally, cargo to a specific destination. The majority of them simply requires to travel from your current location to one destination, the remaining four require to visit a specific port first and then travel to the final destination.

The following text is extracted directly from the game files. The reward is always a random amount of gold piece (determined by the game), usually between 1 000 and 10 000 Gold Pieces.