Locate the weak pirate in Tunis and bombard him when he leaves. Challenge him to a duel and weaken him to 50 hit points. After the duel ends challenge him again to another duel to gain more experience. Repeat this as many times as you desire.
Accept the Collect Debt job in the Venice guild after starting a new game. Get the five gold ingots, deposit in the bank and return to Venice. According to the banker, you have failed the job and reduce your fame but the gold will be in the bank.
When you stop off at a port with an item shop, go to the hotel and sleep until 2am. Go over to the item shop, the shop keeper will say that he has some rare items for sale for a limited time, You can get some pretty cool stuff (many star rank weapons and armour and the occasional tax free permit) but beware, you will need a lot of money. 300000+
This is pretty easy thing to do, get any ship you want (even your starting ship) and get over into the Med sea, and get to Athens Try and empty you ship of as many supplies as possible (as you wont need very many, 3 days worth 5 if youhave difficulty sailing). Fill your ship up with as many units of 'Art' as possible then head up over to Istanbul (North West) and sell the Art there. Then from the Istanbul trader buy 'Carpet' making sure you have enough room for your supplies. It takes a bit of time to do, but I did it for a week and I already have 3.7 million, a full rigged ship, and a Magic Masamura (go to Sakai in Japan Item shop at 2am. You WILL need a lot of money to buy it).
The Merchant will always discount the price of his goods at the rate of 75.0% of the full price. Don't pay more than 75% of the cost of an item, you'll be able to get this discount even if you do not have a good bookkeeper. Make sure the port is an allied one. You do not have to have a Tax-Free Permit but it will reduce your price even more. Also, if you have a book-keeper they will do all the work for you.