I'm thinking different people would put different things on a top ten list and it would be fun to compare; what would you want to know right away (and maybe you learned the hard way or you learned to late) as a new person?
(items not in order of importance)
1. Level one weapon that can attack anybody for use in those "omg, can I really kill that big thing?" situations. Having a weapon a few levels higher than what the game planners expect can mean sailing quickly through quests.
2. Dagger, more specifically, throwing knives, pick up rep faster for a new player (this might be your answer to 1).
3. Low level players can attack a big boss like Darkhart or Blanco if there are five or more other players attacking him and you wait to let them start the fight.
4. Yellow is a good color for an enemy if you are leveling. Yes, you can kill a red but it takes more time and don't forget the time you wait to recharge your health.
5. Keep a notebook to help you remember things about other players--who is more compatible with your play style?
6. You can level sailing and cannoning by cannoning away all or most of the sails and then and then using the ship (sailing) to sink the enemy.
7. Leveling the weapons you don't like a little higher is a faster way to increase your maximum health and you want this to for when you have to attack something "bad" for a question.
8. When sailing, don't be shy about running and porting to keep the plunder.
9. Have a getaway escape in mind -- you can run into a shop or jump into a boat to escape an attack by some unbeatable foe. Maybe this is a little bit on the cheating side, but then again, the game cheats when, moments from you diminishing red health death the computer freeze up for three seconds (nothing you click works even though the buttons in theory should be pushable) while the server tries to think of any possible way to finish you off and you can almost hear the server saying "recalculating.."
10. You can level a lot faster or move through a part of a quest a lot faster if you have someone healing you. Talk with people about what they are doing and what you are doing. A leveling person might enjoy helping with part of a quest.