Tips for people playing Gothic 2 gold edition (aka Gothic 2 + Night of the Raven expansion) for the first time.
Collect every apple you find. For every 25 apples you eat, your strength stat increases by 1.
Collect every dark mushroom (Dunkelpilz) you find. For every 50 dark mushrooms you eat, you gain a permanent +5 bonus to your mana pool.
Scrolls that allow you to transform into a dragon snapper are some of the most OP items in the game. When in doubt, transform into a dragon snapper.
Rain of Fire is devastating in this game (which may surprise you particular if you've just played the G1 remake). When in doubt (and a dragon snapper won't cut it), cast Rain of Fire. Buy every scroll you come accross. If you're a mage, Rain of Fire should also be the first rune you create once you reach the 6th Circle of Magic.
Storm (Unwetter), sold/taught by the water mages is Rain of Fire's little sibling and will do for you in the early chapters what Rain of Fire is going to do for you late game (i. e. clear entire rooms/buildings).
Rain of Fire, Storm and other AOE spells do not respect walls and ceilings. Do not cast this close to friendly NPCs/quest NPCs you want to keep around. In particular, DO NOT CAST these spells trying to clear the sewers under Khorinis if you still want to have merchants to trade with once you're back topside.
Paladins are fine without using runes. If you don't really wanna invest in magic, don't. You only get a very limited selection of runes and your damage spells mostly only work against Demons, Dragons and the Undead. However, against those types of enemies, they are very effective.
If you plan on learning alchemy, don't eat dragon roots or goblin berries. You can turn them into potions. If eaten raw, these plants increase your stats by 1 point. Potions increase stats by 3 points.
If you plan on brewing stat potions, never eat or sell King's Sorrel (Kronstöckl). There's only 25 of them in the entire game and you can't brew stat potions without them.
That said, try to save your permanent bonuses (at least the ones for your main stat(s)) for the mid game game (some people recommend saving them for the endgame, but who has that kind of patience?). Character progression in Night of the Raven is very costly. The LP cost for increasing your stats with teachers increases the higher your stats are. For example, if your DEX is 10, you need to spend 1 LP to increase DEX by 1. If your DEX is 30, you need to spend 2 LP, 3 LP at 60, 4 LP at 90 and so on.
IMO it's best not to start using permanent bonuses before you're about to hit the 60 point threshold.
Once you start chapter 2, you can choose to return to the valley of mines or continue with the plot of the expansion. Even though it's tempting to return to the place you know from the first gane/remake, I recommend playing the expansion first, at least up until the point at which you're tasked to talk to a specific ghost. The expansion is slightly easier and you're going to need the extra levels early, especially if you're a mage.
Snaf will ask you to brew a potion at some point. Samuel can brew the potion for you if you bring him the recipe, saving you from having to collect the ingredients, some of which are hard to find if you don't want to invest skill points in learning hunter's skills.
Learn to how to remove the stringers from bloodflies and how to remove the poison from the stingers. You will be able to eat the stingers, instantly and fully regenerating your health. You can learn both skills from Edgor for 1 LP each. You'll find him in the swamp if you follow the expansion's storyline.
DEX is kinda OP in this game and a useful stat to increase for most builds. People who play mercs/dragon slayers often end up running quality builds (STR/DEX) and mages often use DEX swords early game before they have access to the fireball/ice lance runes and as a backup for when they run out of magic, because the stat requirements for DEX weapons are lower than for STR weapons.
In this game, unlike G1/Remake, acrobatics/combat roll is not a skill you can learn. You gain the ability automatically once you reach 90 DEX. If you were going to level DEX high anyway, this is a good threshold to aim for.
Be nice to Thekla. Just in general, she's under a lot of stress. But especially if you run a STR build. Her stew gives you a permanent STR bonus. You can multple helpings if you do quests for her.
If you want an extra STR point, don't talk to Thekla until you've joined your preferred faction. She'll hand out a freebie to mercenaries/dragon slayers, novices/fire mages and paladins. Militia boys don't get anything. If you went with the militia/paladin route, I don't think it's really worth it to wait talking to her until you're a paladin though, it's only a single point.
Once you're nearing the end of the game, you will be able to pick multiple NPCs to accompany you on your final quest. Paladins should always bring Girion along in order to be able to complete a faction-specific quest. Mages should bring Vatras for their own faction quest. Dragon slayers are fine no matter who they pick (but if you manage to convince Torlof to join you I'm kinda gonna judge you on moral grounds).
Asking Vatras to join you on your quest will cause Myxir to become unavailable as a teacher. So make sure you learn everything from Myxir you want to learn before you invite Vatras (in particular, you'll want to learn all 3 dialects of the Builders' language.
If you're a mage, you need to pick which spells to craft runes for. There are not enough rune stones in the game to craft every rune and only very few runes can be found by exploring.
For this reason, if you're a mage, you should hold back on turning in Fernando to the militia until you've finished the quest "Fernando's Business", since he'll reward you with a rune stone (this chapter is available from the beginning of chapter 2). You can still sell him out in chapter 3.
Fire mages, don't sleep on the water mages' magic! Ice lance is going to be your Fireball against enemies with high fire resistance (such as wargs). If you learn only 2 spells from Circle 2, they should be Fireball and Ice Lance.
Learn sneaking and lockpicking as soon as possible. Sneaking isn't just great for robbing people, it also lets you sneak around monsters that are too strong for you in the early game. It also allows you to loot shadow beasts' lairs right at the start of chapter 1, since shadow beasts sleep during daytime and as long as you sneak, you won't wake them up even if you walk right up to them.
Occasionally check back in with Xardas. There is no gameplay reason for this, he's just gonna be really sarcastic if you report in before you've actually finished any of the main quests.
Be supportive towards Lee. Again, no gameplay reason for this, he's just having a rough time.
Don't stress about Gorn in chapter 2. If you're really that hard on cash, Milten is going to get him out on his own (he's only going to have to break his oath to do it 😔😔😔. Don't stress about that either. Nobody will ever know).
If you're running a melee build and you finish the expansion's storyline, you may come to believe that the sword you receive at the end of the expansion's storyline is all you're going to need to finish the game because it's just that OP. This is mostly true. You will likely use this sword until the end of the game. The sword IS that OP. You should still make sure you got a second weapon you like and that works with your build once you cross the Point of No Return (the Point of No Return is clearly telegraphed in this game, btw. it involves a ship). Don't worry, the OP sword is not going to be taken from you at any point. It will be right there with you until the every end. Still, just keep one other high damage endgame weapon on you so you have a backup that isn't a rusty Zweihander you picked up from a random enemy. Trust me. You will be laughed at if you don't.