At night, go alone to somewhere people never go, and completely nullify yourself to G-d
The primary hisbodidus is at night, for then everyone is sleeping, and also that the place should be outside the city, that he should go on a solitary way, that is, in a place where people do not go there even in the day. And through this that one does hisbodidus at night on a solitary way as mentioned above, and clears his heart and mind from all engagements of this world, and abnegates everything, until he nullifies himself completely; meaning, that first he prays copiously until he abnegates this vice, and afterwards [he continues to pray copiously until (Outpouring of the Soul)] he abnegates a different vice, and afterwards [he continues to pray copiously until (Outpouring of the Soul)] he utterly nullifies himself, that he should not retain any haughtiness or any entity, until he is in his (own) eyes as literally nothing and void, and through this he merits to come to the aspect of true nullification, and through this his soul is included in its root [in His infinite (Ain Soaf) unity blessed He, which is called the michoo'yuv hamitzee'oos (imperative <of> existence), as is known (Outpouring of the Soul)]. And through this the entire world is included with him in its root, that is, it is all included with him in His Unity blessed He.
(Likutay Moharan 52; Outpouring of the Soul 59 – at much greater length).