Proper intention in Teffilah:

It is written in the Yishai'ahu (29:13) "With his mouth and lips he honored me, but his heart distanced from me". The Gemara (Nedarim 62b) says "act upon things for the name of the work". In the Gemara Rosh HaShana (29a) there is disagreement whether Miswot require proper intent. The Rosh holds (Rosh HaShana 29a) that Miswot, indeed require proper intent. So has written the Shulhan Arukh (Hilkhot Keriat Shema 60:4). One should not utter the name of Hashem without having the proper intentions. This is brought down in Sefer Haredim (Siman 56), and in She'elot U'Teshubot Yafeh LaLeb [Rabbi Haim Palagi, 1788-1878] (Siman 101).

Maran [Rabbi Yosef Caro, 1488-1575] writes; Shulhan Arukh (Orah Haim 5:1), that when one utters the name of Hashem (Yud-Keh-Waw-Keh) he should concentrate that "Hashem is the master of all: is, was, and always will be." Maran continues, that when someone states the name of Hashem (E-lokim), he should intend that "Hashem is all mighty, master of (man's) ability, and master of the power in the world(s)." The Or Lesion [Hakham Ben-Sion Abba Sha'ul 1924-1998] writes (Or Le-Sion, 2, 1:19) that this specifically speaking of Berakhot, that one must have in mind "Master of all: is, was, and will be". The Hida writes (Birke Yosef, Siman 101), that it is praisworthy to have this concentration on every utterance of the name of Hashem. So wrote the Ben Ish Hai (Parashat WaYesheb 3).

The Ari HaQadosh explains that when someone utters Hashem's name (Yud-Keh-Waw-Keh) they shall concentrate on the name of Hesed of Hashem (as brought down in most Sefaradi Siddurim).

In the Sefer Afike Yam, Rabenu writes that one should make a condition in the morning that every time that he utters the name of Hashem, it shall count as if he intended on those centralizations (as brought down on the first page in Siddur Abodat Hashem). Rabenu Massliah Ma'azuz writes (Haga'hot Al HaMishna Berura), that this condition does not count for the first Passuk of Shema Yisrael.

The Kaf HaHayim (Orah Haim, Siman 107), the Magen Abbraham (Orah Haim, Siman 101), and the Shulhan Arukh HaRab (Orah Haim 5:1) write, that when one utters the name of Hashem (Alef-Dalet-Nun-Yod) he shall concentrate on only "Master of all".

In conclusion, it is proper intend on all of these intentions, but if one is unable to, he may say the condition as mentioned before, or he may say "LeShem Yihud" before each activity of Miswa Dehoraita or Derabbanan. Rabenu Dawid Yosef writes (Osrot Yosef Siman 20) that it is a attribute of righteousness to say Leshem Yihud, but continues to say that one must be very careful not actually verbalize the letters of "Shem Hawaya" rather say "Yud Keh-Waw-Keh". It is brought down in the Mishna Berurah (quoting a Gemara) that one who verbalizes the name of Hashem loses his part in the world to come. So we must be meticulous on this aspect.