The first verse of Shema – "Shema Yisrael Hashem Elokenu Hashem Ehad" – is printed in the Siddurim with an enlarged letter "Ayin" in the word "Shema," and an enlarged letter "Dalet" at the end of the final word, "Ehad." (These two letters spell the Hebrew word "Ed" – witness.) The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in Parashat Va’era, writes that when one recites this first verse of Shema he should visualize in his mind the enlarged "Ayin" and the enlarged "Dalet." Besides verbalizing the words, one should also try to picture in his mind these two letters in their enlarged form, as they appear in the Siddurim.
The Ben Ish Hai also rules (in Halacha 11) that one should make a slight pause after completing the first verse of Shema, before reciting "Baruch Shem Kebod Malchuto Le’olam Va’ed." One should then make another slight pause after completing "Baruch Shem…" before proceeding to "Ve’ahabta." And while reciting the word "Malchuto" in "Baruch Shem Kebod Malchuto," one should lower his head. The Ben Ish Hai writes that there is profound Kabbalistic significance to lowering one’s head during the recitation of this word during Shema.
Summary: While reciting the first verse of Shema, one should visualize in his mind the enlarged letter "Ayin" in the word "Shema" and the enlarged letter "Dalet" in the word "Ehad." One should make a slight pause after the first verse of Shema, and another slight pause after "Baruch Shem…Le’olam Va’ed." One should lower his head while reciting the word "Malchuto" in "Baruch Shem…"
