Maritime Guide (by Athrun)

Battle LVL 1-10
At this range it is best to enter school.

Battle LVL 10-17
At this range it is best to enter school or Visit Genoa and do the quest for maritime guild there.
It is recommended to fleet with others to complete this quest.
But soloing is also possible.

Battle LVL 16-25
At this range you can complete the Advance Maritime School at Pisa.
Visit Genoa and do the quest for maritime guild there.
But this time you can solo for more exp.
But depend on quest you can fleet up.
Try for 4 Stars Quests. Make sure you purchase Fafnir kind of equipments to take advantages of Cannon Evade.
Visit Saint Georges and exp off pirates near by.
This location differs from Genoa since its solo based.
Enemies are pretty strong here and also equipped with strong cannons so be advised.
Congo Pirates are very tough and its my recommendation to avoid these at all cost.

Battle LVL 16-32
Stockholm or Santo Domingo.
If you have a decent level on Adventure or Trade, then you can easily try out Stockholm at this level since you can customize your trade or adventure ship to be ready for battle. Otherwise its recommended to goto Genoa & Saint Georges. At Stockholm, you will be mainly repeating Guild Quests. Watch out for Swedish Pirates since they have very strong cannons. At Santo Domingo, Guild quest levels are much higher so you will be mainly leveling off pirates around that area. This location is considered best exp method compared to other places that I mentioned at this level section. Travel from Santo Domingo <-> SanJuan and level off there. Not recommended for Melee since Pirates have all types of skills. Battle LVL 25-35 Cape-Town Repeat some Quest there for decent exp while leveling off pirates around area. Many pirates use Incendiary Shots here so make sure to be prepared for this.

Battle LVL 25-36
Athens and Black Sea If Cape-Town is too far for you to travel, these locations are also recommended.
Lot of galleys in the area so this is where the S Bombardment skill comes in.
If you are not familiar with this skill/tactic, please refer to the section on tips-guide regarding this.
In order to get equipments for your ships you can visit Istanbul but make sure you have enough disguise level.
Travel from Odesa -> Kefe -> Trebizond and fight the Large/Heavy Galleys.
Also its not good idea to fight NPCs with the Ottoman flags because this will block you from entering Istanbul (where you will be getting equipments and stuff).
If the Ottoman Flagged ships attack you, you can take them out since by you defeating them you wont gain any hate toward the nation.
Hate happens only if you attack first.

Battle LVL 25-42
Zanzibar You will be sinking Galleys and Sambuks here.
If you are cannon oriented, then go for Galleys.
If you are melee oriented, then go for Sambuks and Xebecs.
Use muscat to purchase your equipment needs.
Quest at this location isnt that bad either.
So try them to maximize your level.
This is what I have so far.
Stay tuned for more guides~ Good Luck.