New Players

Quests

There is a main quest. When you first enter, you should speak with Sedos, who will initiate you into the academy. You can get some training downstairs (free level up!), after which you should report back to Sedos and retrieve the remaining quests.
There are quite a few side-quests. If an NPC is named, it is likely they are a source of interest and may have a side-quest for you!

Certain item types are more rare than the others. As an example, bows, longswords, greatswords, axes, etc. are the most common types of items, and you will find more good ones of that type than others, whereas item types such as scimitars, full-plate, and shurikens are one of more rarer types. So, it's a good idea to focus or specialize on the more common item types.

XP percentage is increased/decreased based on your wisdom.
Multi-class XP penalties are disabled.
Having at least one level in your favored class will grant bonus XP. Alternatively for humans and half-elves, being dual or multi-classed applies an XP bonus.

Henchman can be recruited for free in the Trade of Blades in exchange for some of the loot and gold.
They can be quite useful in overcoming difficult encounters, and there is no limit to how many you can have at once. However, recruiting more than one will require a persuade check, with increasing difficulty based on how many you have.

Militia can join you after you have finished the academy, free of charge. If you are having difficulty in a quest, it can be wise to take advantage of the militia.
Note that unlike henchman, they will not decrease your loot. However, they will still detract from XP gained.
Recruiting more than one militia recruit will require a persuasion check, with increasing difficulty based off the amount you currently have.

Resting in a dangerous area has a chance to cause an ambush. Having a level in ranger or being partied with one will reduce this chance.
Rests are linked, so it is not possible to cause multiple ambushes when more than one player is resting nearby.
Enemies encountered from rest give reduced XP and never drop loot.

Certain districts have different kinds of merchants.
Pawnshops such as Olgerd in the Docks district will buy items at the best price.
Items sold to stores will be transferred to their local pawnshops.
Only Eltoora in the Cloaktower will identify items.
Buying and selling items are affected by both your charisma score and your appraisal skill.

Respawning results in loss of XP and Gold, and will teleport you to the nearest Temple of Tyr. You will never lose XP below your current level.
You and your henchman will be automatically revived if there is a friend nearby. This is similar to NWN 2/KotoR. Only a complete party wipe means no recovery. Therefore, it is a good idea to travel with a friend, even if it is a henchman for the possibility to be revived and prevent the loss of XP and gold.
This mechanic applies a stacking constitution penalty that can only be removed by respawning or healing at a temple. Also, you can only be revived by this revival mechanic three times, afterwards you can only come back through respawning or through raise dead.

If you have made a mistake when leveling up, etc. you can go to the Academy in the Beggar's Nest district and talk to Geldar. He can put you back to level 1 and give you the equivalent of your current experience - for a modest fee, of course. As always, he can persuaded for a lower cost.

You can modify and dye your items in the Divine Elegance shop in the Blacklake district in Neverwinter. You will have to pay before entering, but you can use persuasion for a lower cost.

Horse summoning stones can be bought at a stables outside of Neverwinter, providing quick travel.
Horses cannot be summoned in combat, and the following cannot be used while mounted: traps, lockpicking, stealth, and pickpocketing.
When mounted, 30% spell failure, -2 AC, and -1 AB is applied due to size (doesn't stack with the penalty with ranged weapons). The spell failure can be reduced by more ranks in the Ride skill.

You can purchase houses in Neverwinter by looking around for vacant houses and interacting with the door.
There are three tiers of houses, each with their own features, costs, storage capabilities, etc.
You can only have one house per CD key. All of your characters under the same CD key will be able to use the house.