Making an interval between Elokaiy and Neshama: One is required to make a slight break between the words Elokaiy and Neshama, in order so it does not sound like one is saying that his soul is his G-d. [The Rebbe Rashab would also make an interval between the words Tehora Hi and Ata Barasa and between the words Ata Barasa and Ata Yatzarta.]
Tehora Hi: In the Siddur Admur writes the word Tehora Hi. Some however omit the word Hi.
Sparks of Chassidus:
The soul’s descent: The prayer of Elokaiy Neshama refers to the descent of the Jewish soul below into the body. The Neshama first starts off in the world of Atzilus. In this level the Neshama is found in complete unity with G-dliness, and is pure and refined, prior to its descent below. It is referred to in the words “Tehora Hi”. The Neshama then begins its descent below to the worlds of Beriya, Yetzira and Assiya. This is referred to in the words “Ata Barasa [Beriya]; Ata Yatzarta [Yetzira]; Ata Nafachta Bi [Assiya]”. The descent into these three spiritual worlds, one lower than the other, effects the necessary changes for it to become invested within the animal soul and physical body.
Returning the soul to unification with G-d: The reason the Sages instituted that this prayer be said in the beginning of Birchas Hashachar, prior to Davening, is because it represents the soul’s Mesirus Nefesh throughout the day. In this prayer we state that “You gave me the soul…and You will take it from me in the future”. This means to state that since You have given me the soul and will eventually take it back therefore I will already now begin to dedicate it and hand it over to you, to unite it within your unification. This will be accomplished through binding my thoughts with Your thoughts and my speech with Your speech, through the letters of the Torah and prayer. It is with this preparation of giving over the soul to Hashem that we begin Birchas Hashachar.
 M”B 46/3; Rebbe Rashab brought in Likkutei Dibburim Likut 23 p. 633
 Likkutei Dibburim Likut 23 p. 633
 Shaareiy Teshuvah 6/7; The reason for this is because the blessing is to contain 47 words in corresponded to the Gematria of the names Havaya Ehye-h. [See Piskeiy Teshuvos 46 footnote 46]
 Torah Oar 71a; See “Lilmod Eich Lihispalel” Vol. 1 p. 55-75
 Tanya chapter 41