This is for Port Royale 1:

Step 1) Use Cheat Engine to give yourself 9 million gold whenever necessary and build up fleets and attack pirates. Note that there are three memory addresses and only one will actually affect your gold level. Save often before changing the memory address to avoid corruption. Build up your sailors and guns and have fun doing it. (repeat as necesary)
Step 2) Make 5 fleets of increasing power, caravels/caracks last by normal game methods + extra cash you got from step 1
Step 3) Position your fleets in a strategic position since military fleets take off after attacking you
Step 4) Provoke a military response by letters of marque or just attacking foreign powers with your weakest fleet.
Step 5) Set all of your ships to grapeshot and deplete the troops of as many of the military ships as possible. Try to maneuver so as to avoid quick boarding attacks by the military fleet
Step 6) Repeat by losing succesive fleets while causing attrition on the mil fleet
Step 7) You should now be in a position to attack and board the mil fleet ships with a strong fleet and capture many military ships.

Enjoy your ill gotten victory!