Speaks for itself.

You can upgrade items by dragging and dropping them onto the same items (there's a visual hint, a green tint). DON'T settle for the first result with the armor — and watch out: at higher class tiers an 'upgrade' can even SUBTRACT the armor value. Save-scam a little instead: get two pieces of armor ready, quick save, open inventory and try an upgrade. On armors with 100s of Protection you should aim for around +100ish for one class tier upgrade. If the results don't satisfy you just load and try again. You can extra save a result that you think is close to the best and then load a save before the attempt and still try a couple more times. It makes sense to do that on the later tiers of gear of course. And it doesn't seem to work with weapons, the results are pretty much the same there as far as I can tell.

NPCs that give you quests or make any meaningful conversation have the green speech icon when you approach them. Trainers have the reddish one. The yellow ones are for generic NPCs. There is an NPC that lets you respec in the first big city of Tharbakin — he has a blueish one.

If you steal from a chest of some NPC and he sees it and starts chasing you — just run away until he holsters the weapon and walks back: this will not affect you future interactions at all.

You don't need any potions or ingredients with temporary effects (EXCEPT for gems). Just mix'em up in any proportions (the more of the same, the better, because it's easier) and sell the potions. You might keep some plants that remove poisoning and give poison immunity though. And those that give plain HP you can mix into healing potions if you like.

DON'T make permanent potions until your Alchemy is maxed out! Find a trainer. This way insread of getting 9 DEX points out of 10 Centaurium plants you will get a whopping 18, and from those that give more than 1 point even more. Don't mix them with the other ingredients, collect a stack of 10. This will make the strongest potions.

Gems when brewed produce stones for weapon elemental enchantments. And in stacks of 5. That means if you mix more you will still only get one 50% elemental stone. So don't waste them. If you want the permanent effect instead of an elemental stone add 9 of the ingredient and one healing or mana potion.

Kill small critters, especially beavers and foxes. Beaver Fat gives permanent Vitality x 2 and Fox Liver gives permanent Dexterity x 3 with 100% probability. Mix a potion of 10 and you'll get a good chunck of a stat for free.

Riding a horse is a terrible experience in this game. Get a horse near a teleport or a vendor instead. Approach it until the horseshoe icon appears and open inventory. Boom — a storage space. Pick a horse that can carry 500 weight (there are some cool looking draconic horses but they can only carry 380). Just remember where you left the horse. You will stumble upon many a horse while playing, you can even sort loot this way if you are so inclined.

1 point of Strength gives 3 points of weight. Invest in it but at around 80 Strength you'll approach the the point where you won't have enougth geometrical space in the inventory to fit all the loot in.

Drop one mobile teleporter (you will get three pretty early on) in some city near a vendor and leave it there to quickly sell the loot.

If the Item Set Number for armor gets into the next decimal (like, 554->561), stop inversting money in upgrading previous tier (unless you the looks). From now on the next tier of armor will drop and appear in shops. Only invest the looted pieces if you don't need cash. Same with the weapons and quivers but check the weight. Weight 6 -> Weight 7 (of the same weapon class) = that's the new tier.

When fighting Cyclopes or Giants or other bigger monsters that can OHKO you use polearms with piercing damage, do a forward attack and then Jump Back (there is a button). It's very effective, much more than kiting them and denting them with the bow.

Most enemies are vulnerable to all types of damage. Skeletons seem to be immune to Piercing or Slashing damage but they really don't like Bludgeoning. Spectral ghost enemies are immune to normal attacks but if your weapon has some sort of elemental enchantment (i.e. fire damage or spirit damage) it will hurt them. Magic also works.

You can choose up to 3 active spells and add some boosters to them on top. I like to have one spell that snares the enemies in place at the ready — helpful for dealing with archers that always try to run away (Earth Magic and Necromancy have such spells).

Whenever you get additional spell cards don't forget to go to the spellbook and manually drag them to the active spell slot. They don't go there on their own so you might end up running with a Level 1 Firebolt for the longest time.