Originally posted by Measuperbia:

Random ticks attackkng you, but no gjall around? -strong indication a skull nearby.

Huge ribbcages allways pair up with a skull.
-Stop looking for skulls and look for ribbcages!

Ribbcages are often paired with a sword sticking into it.
-start looking for "sword shapes" in the mist.

I really feel skulls are not that rare..

1. Ribcage maybe, skull not necessarily.
   
2. Not true, plenty of ribcages without skulls.
   
3. Perhaps but not in my experience. Saw that maybe once.
   
4. I found there was enough skulls, but that was one run and Valheim is very RNGesus.