The Black Forest is, imo, where you'll do the most sneaking of your play through.
Get comfortable with sneaking. Turn the music down a bit and slap on some headphones. Keep your eyes and ears open, the trolls can seemingly appear from nowhere.

Do NOT explore at night. Sleep through the night if you can. Greydwarves spawn like crazy at night, and they can be hard to see at a distance due to the hills and trees.
The worst thing that can happen in your early BF adventure (besides multiple trolls, lol) is running into a TON of GDs at night, and not being able to escape because you have low stamina due to bad food. EAT AND EAT WELL!

Fire arrows are a good investment for your new enemies. Otherwise, save your materials and only make wood arrows for most things.

The ghosts totally suck, but they're rare. You'll find maybe 1 in every 10 or so crypts might contain a ghost. Their attacks can be blocked, but you may want something better than a wooden shield. The worst thing about them is they have no attack animation, so you'll need to learn the timing of their attacks to know when to block. Honestly, you should try avoiding them until you have better gear. There are always more crypts.