Avoid walking through disembodied spirits. It only irritates them. Avoid joining your life force to anything with glowing red eyes. If asked to sign a contract or pact and you are experiencing doubts or reservations, sign your neighbor's name. While drunken weaving may be mistaken for ecstatic dancing, slurring the names of the Dark Lords is generally considered bad form.
Blood IS thicker than water.
Soak sacrificial ritual garments an extra 30-45 minutes.