Don't rush into a big ship until you have a well-developed trade route. The large hungry crew will eat up your profits.
Pay attention in school! Believe it or not you can learn a lot how to play the game by reading everything carefully. Also it's a good place to meet other people starting out as you.
Make sure you are very well prepared before starting out on any voyage. The game is very unforgiving of mistakes. Check your provisions before setting sail and make sure you have enough supplies to last until you reach the next port.
Language skills as well as other skills can be found in the guilds as well as the important people in the towns. Go in your school clothes and visit them.
At least learn the body language skill (25,000 in London). Get beat up by pirates and you can end up in a town with no money, no crew, and no way to get to your insurance or bank cause nobody can understand you. Not fun!
Slow down and talk to the NPCs. Lots of good stuff here: hints, trade routes, gifts, etc.
If you find that honey of a trade route use it quickly. Others will learn of it fast and it will be gone.
Don't like your school uniform? Get used to it! It gets you into places you will need to play the game.
Try to keep some junk stuff in your inventory. It will hopefully absorb some of the durability damage your equipment takes when you get into trouble instead of your good stuff.
Be careful of who you buy from. Some of the stuff I have seen players selling has been marked up 1000% In all fairness I have also seen some great deals.
Be careful of whom you travel with. Some can lead you into privateer ambushes!
Do not attack a privateer in safe waters unless you are sure you can take them AND any possible fleet they are with.
You can grind levels fast by purchasing spice in a bazaar and then selling it one at a time in the market. This is a bad idea for a low level player for several reasons.
The game is skills-driven not levels-driven; yes with the higher levels you gain port access and the ability to sail a larger ship--but without the concomitant merchant or combat skills you are actually worse off than if you spent some time leveling them.
You do not have the vigor to make long voyages unless you have lots of food and if you cannot fish at rank 5 or higher, you cannot support your crew by fishing alone.
If a pirate sees a 9-29-5 merchant and a 17-32-20 merchant, who's he going to attack? Buying levels with spice simply makes you a pirate magnet.
The items above mean that you get frustrated with the game and abandon it. Enjoy the lower levels and figure out the game. Don't try and grow up too fast.
Use the spice trick only to gain a level you've almost achieved or to build a little fame.
Everybody, even a combat-oriented player, needs some merchant skills. You absolutely need Accounts and probably one production skill with the two or three associated merchant skills. For example: Cooking needs Livestock and Food Trading and Seasoning Trading. Other merchant skills you want are Accounts, Frugality, Body language and Storage.
Pay attention to your fame. Fame is how you get port permits. So spend some time doing Guild Quest and the Event Quest while you are in school over time those will boost your fame levels and you'll not need to resort to selling spice.