Talk to your party members all the time and exhaust all dialog with them, anything major happens talk to them again.

Pharod will ask you to fetch something. Later in the game you'll be able to get it back, do so and don't leave it anywhere.

There's an tattooed arm in one of the crypts under ragpickers square, take it to Fell and make sure you have Dakkon translate when you ask him about it.

There's a seamstress called Marta under ragpickers square, ask her to look around inside you.

Don't throw any of your body parts away even if they seem useless to you.

There's a zombie worker on the ground floor of the mortuary who knows you.

Stale-Mary can teach you an important skill if your INT/CHR is high enough.

The Modron toy has secrets. 3 of them.