Alright, well I know that there are a lot of other posts about becoming a pirate and what not, but like many others when I became a pirate I was totally clueless as to what I should be doing. So here is a little guide to help you out in your journey to becoming a pirate.
BTW, this is all to my best knowledge, everything here is gained through in-game knowledge so there may be a few mistakes.

First of all...
There is nothing really different of a pirate than that of a regular player. both do the same thing except pirates get a different type of title and are also allowed to extort from players (granted they have atleast 32 seabattle).

There are three main types of pirates that you can be. Crete, Corsica or Tortue.

The Crete pirates are hard to be since when you first start the game you usually go fight a lot of Crete ships to get your Seabattle up. But if that is what you want to be then you will have to go to Crete Island which is located South of Athens. You must have atleast "0" amity with the Crete (meaning that you can not attack any crete pirates... . Along with that, there are no officials for pirates, if you want your rank to be higher you must fight the "good" guys. In order to get amity with the Crete pirates you will have to kill ottoman empire and greek empire ships (anything from Istanbul, Beirut, Athens, Alexander will do). Once you start attacking these ships you will lose amity with the city you are attacking and the glory frigates and Patrol ships will attack you. These are very strong and you will end up dieing more than likely.

The next would be the Corsica pirates. Corsica is located south of Genoa (as shown in the picture above. Once again it is the same as the Crete. Except this time it isn't the Ottoman and the Greek you must kill. I am not too sure which ships you kill for the amity in this but it is very similar to that of the Crete. You just kill ships, get amity and buy the title.

Now, the most widely known and used pirate is the Tortue pirate (Carribean). Totue is a pretty long ways away from land. I suggest going to Madeira, stocking up onprovisions and then going. Once you get close you may see things that look like cities without a port... don't worry, it is meant to be that way (maybe IGG plans on making them cities later on). but anyweays, just like any other pirate city this will just show up as a docking anchor and once inside you dop not have to fight past any ships, it goes straight to port.

The Tortue pirate is used most mainly because it is the easiest to gain amity, there are missions that will allow you to become a better pirate, plus it is an entire city, not just a little island.
I suggest you have atleast a level 4 battleship to become a pirate mainly because if you want a better title than "Wanderer", then you need to be able tokill some white ships (white ships meaning the "good" cities' merchant ships). Once you are at Tortue you will need to start killing ships. Right North of Tortue is a trade route where only merchant ships, darkdiamonds, and a boss will go through (none of these will aggressively attack you, so you are safe f01 ). The levels of the ships start at 6 and are: Pearl, Ruby, Sapphire, Gold, diamond, Darkdiamond **(these are actually very strong battleship merchants).
In order to get very high mity follow this...
0-10 pearls+
11-20 Rubys+
21-30 Sapphires+
31-40 Gold+
41-50 Diamonds+
50 and up you must kill glory frigates and patrol cruisers (not sure but I believe Darkdiamonds will do as well)
All these ships will be portugal, spain, English, or the Dutch in order to gain amity, and while dong this you may get either Carribean or Gibraltar amity.

You may also sit outside of Las Palmas (the little Island on the way to Africa) killing Agate trading ships. These ships will give you 5 amity, the same as diamonds, all the way up until 50 amity. This would be a much easier way since it is only one ship that you have to look for and it is closer to the gibraltar Battlefield which is where you must go to win back amity with Spain and Portugal. The only problem would be you must look out for Glory Frigates and Patrol Cruisers unless you are a high level BattleShip.**

So, now that you are a Carribean pirate, you should probably try some missions. The missions that I have seen/heard of are:
1)Take rum from the docker to the Pub 2)Get 2 trade vouchers from boarding merchant ships and trade to the arm Peddlery 3)Get 5 trade vouchers and trade to the Loricae Peddlery 4)SINK (not board) 25 rubys and 25 sapphires *Disposal of stolen goods lvl2* 5)BOARD (not sink) and kill 25 gold level ship captains (if you remember well... Golds are level 9, this is a hard quest... lol *Extortion lvl 2* 6) There are 3 different lost documents that you have to find 7) Board and kill Royal Charlie...

Well those are all of the missions that I know about in Tortue
After doing a couple missions you will unlock the black market whichholds (what I have hear) very good items that you can buy with a decent amount of trade vouchers.

Alright, Well I believe that is everyhting about pirates there is to know...