The Rebbe's guidance on troubling dreams, superstitions, the evil eye and "signs":
Don't be disturbed by dreams. Don't dwell on troubling dreams or perceived signs; they are generally insignificant (IK 7504, 7622, 5504). Instead, take practical steps — check mezuzos and tefillin, give tzedakah, and strengthen trust in G-d (IK 1745, 4333, 4666). Ignore unfounded worries that come from dreams, for instance during pregnancy (IK 10328). Mundane thoughts easily show up in dreams; spiritual growth comes through steady Torah study (IK 8439). Seeking answers through dreams is only for rare situations; focus instead on Torah and proper conduct (IK 2149, 8841).
Dreams of tzaddikim and departed parents. A dream of the Previous Rebbe is a good sign, calling for more Torah study and good deeds (IK 5107). When one dreams of a departed parent, it is worth checking that the burial was proper and the mezuzos are kosher (IK 5768).
No room for superstition. Superstition has no place in a Jew's life; trust instead in G-d's personal Providence and follow His Torah (IK 5532, 5942). Don't rely on palm reading, charms or amulets — trust in G-d and Torah are the true protection (IK 2848, 3995, 5383, 9397). In choosing a shidduch and setting a wedding date, be guided by Torah and trust in G-d, not by superstitions or foreign customs (IK 2396, 5974).
The evil eye. Don't focus on ayin hara; strengthen mitzvah observance instead — check tefillin and mezuzos, and trust in G-d (IK 4363).
See also: Bitachon – Worry, fear and anxiety; Health – Checking tefillin and mezuzos.