The Rebbe's teaching on how to receive a blessing — his own and G-d's:
A blessing needs a vessel. To receive blessings from Above, one must make fitting vessels below, above all through daily Torah study — daily Chumash, Tehillim and Tanya are effective vessels (IK 1267). Torah and mitzvos are the true channel for G-d's blessings, while natural effort is only a means to make a vessel for what has already been decreed Above (IK 7262). Linking a good resolution to a concrete action strengthens its fulfillment (IK 6680).
Adding brings more. Every increase in Torah and mitzvos draws additional blessing in all one's needs, especially when special blessings are needed (IK 9587, 9902). Someone who writes only about material needs should know that Torah study and chassidic gatherings are the true channels for blessing (IK 2508). Revealing one's inner purity makes one a vessel for both spiritual and material blessing (IK 5545), and even a small opening of the heart to G-d brings abundant, unending blessing (IK 2863).
The source of blessing. Human blessings are limited, while true blessing comes from its Source Above (IK 6533). On the unique power of a Rebbe's blessing, and checking mezuzos as a standard precaution rather than a suspicion, see IK 3637. On the significance of specifying details in blessings, see IK 1868.
See also: Bitachon – Trusting G-d and doing your part; Tzedakah – A source of blessing for health, livelihood and family; Faith and Chassidus – Hiskashrus: connection to the Rebbe and tzaddikim.