Weapons

To re-forge your steel sword, you'll need three meteorites. To re-forge your silver sword, you'll need three runes. To complete the re-forging, you'll need to visit a blacksmith and select the "forge" option. This will bring up a shopkeeper interface, and all of the potential swords that you can create will be listed as items to buy.

It isn't possible to re-forge named swords.

You won't pick up a silver sword until Chapter II.


Herbs

You won't be able to pick herbs until you've learned the Herbalism skill. You'll also need to know about the herb in question (by reading about it in books, or by learning about it from people) before you can pick it.

Herbs will grow back in time, allowing you to pick them again.


Conversations

If an NPC stops talking to you, or if they tell you to come back later, then leaving and re-entering the map location with the NPC will allow you to deal with them again.

Sometimes NPCs with anonymous names (like "peasant woman" and "gossip") will have interesting things to say. So you should talk to everybody.

Sometimes grey dialogue options can lead to new conversation topics.


Miscellaneous

Once you've learned the Igni sign (most likely in Chapter II), you'll be able to use it to light fires. However, you won't be able to use signs in safe places, so you might still need Flint.

Locks can't be picked or bashed open in the game. There are many doors that you just won't be allowed to open.

If an enemy is carrying a quest item, then its remains won't disappear until you've picked up the item. This is most useful with trophy bosses, since you can only carry one trophy at a time.

Cat potions are far more useful than Torches. You should always keep some around.

If you loot a corpse and see "skinnable items available," that just means you've read up on the creature you killed, and some of the items might only be there because you learned about them. It doesn't mean that you'll actually need to skin the corpse to get more items.