Next, he (صلى الله علیه وسلم) would commence his recitation with many kinds of supplications in which he would praise Allaah the Exalted, and glorify and extol Him. He in fact ordered "the man who prayed badly" to do so, saying to him:
"No person's prayer is complete unless he says takbeer, praises Allaah the Mighty and Sublime and extols Him, recites of the Qur'aan what is easy for him ..." 
He would say any one of the following supplications:
"O Allaah! Separate me (far) from my sins as you have separated (far) the East and West. O Allaah! Cleanse me of my sins as white cloth is cleansed from dirt. O Allaah! Wash me of my sins with water, ice and snow."
He used to say this in obligatory prayers. 
I have set my face towards the Originator of the heavens and the earth sincerely [in Islam] and I am not among the Mushrikeen. Indeed my prayer, my sacrifice, my living and my dying are for Allaah, the Lord of the Worlds: no partner has He. With this I have been commanded, and I am the first of the Muslims (those who submit to Him).  O Allaah! You are the King, none has the right to br worshipped but You, [You are the Most Perfect & all Praise is for You] You are my Lord and I am Your slave . I have wronged myself, and have acknowledged my sins, so forgive all my sins, for no-one forgives sins except You. Guide me to the best of characters, to which no-one can guide except You, and save me from the worst of characters, from which no-one can save except You. I am here and happy to serve you . All good is in your Hands, and evil is not from You.  [The guided one is he who is guided by you.] I exist by your will and belong to You. [There is no escape or shelter from You except to You.] You are blessed and exalted. I seek Your forgiveness and repent to You.
He used to say this in obligatory and voluntary prayers. 
- Similar to the above, without"You are my Lord and I am Your slave" to the end, with the following addition:
"O Allaah! You are the King, there is no (true) deity except You, glorified be You and praised." 
- Similar to no. 2 until"and I am the first of the Muslims", adding:
"O Allaah, guide me to the best of characters and the best of actions, no one to which can guide except You, and save me from the evil characters and actions, from which no one except You can save (others) except You." 
"You are Glorified , O Allaah, and Praised ; Your Name is Blessed ; Your Majesty  is Exalted, and none has the right to worshipped but You." 
He (صلى الله علیه وسلم) also said,
Indeed, the words most loved by Allaah are when His slave says: You are glorified, O Allaah 
- Similar to the above, adding in prayer at night:"There is no true god except Allaah," three times, and"Allaah is the Greatest, Very Great," three times.
"Allaah is the Greatest, very great. Praise be to Allaah, again and again. Glorified is Allaah morning and evening."
One of the Companions commenced with this, to which the Messenger (صلى الله علیه وسلم) said:
"Wonderful for it (the supplication) is that the doors of the heavens were opened for it. 
"Praise be to Allaah, many, pure, blessed praises.
Another man commenced with this, to which he (صلى الله علیه وسلم) said:
"I saw twelve angels competing as to which of them would take it up. 
"O Allaah, to You belongs all Praise. You are the Light  of the heavens and the earth and all those in them; to You belongs all Praise. You are the Maintainer  of the heavens and the earth and all those in them; [to You belongs all Praise. You are the King of the heavens and the earth and all those in them] to You belongs all Praise. You are the Haqq ; Your promise is haqq; Your saying is haqq; meeting You is haqq; Paradise is haqq; the Fire is haqq; the Hour is haqq; the Prophets are haqq; Muhammad is haqq. O Allaah! to You I have submitted; in You I have placed my trust; in You I have believed; to You I have turned; for Your sake I have fought; to You I have referred for judgement; [You are our Lord and to You is the end of all journeys: so forgive me my earlier and later sins, what I have concealed and what I have showed] [and whatever else You know about more than I.] You are the Bringer-Forward and You are the Delayer; [You are my deity;] and none has the right to worshipped but You.  [and there is no might nor power except with You]."
He (صلى الله علیه وسلم) used to say this in prayer at night, as he did the following supplications: 
"O Allaah, Lord of Jibraa'eel, Meekaa'eel and Israafeel, Creator of the heavens and the earth, Knower of all that is hidden and open! It is You that will judge between Your servants in those matters about which they used to differ. Guide me by Your Grace to the Truth concerning that about which they differed, for indeed You guide whomsoever You wish to a path that is straight." 
- He would say takbeer, tahmeed, tasbeeh, tahleel and istighfaar ten times each, and then say,"O Allaah! forgive me and guide me and give me sustenance and [overlook my sins]" ten times, and then say:"O Allaah! I seek refuge with You from the distress of the Day of Account" ten times. 
"Allaah is the Greatest [three times], Possessor of Kingdom, Power, Magnificence and Might." 
 Bukhaari , Muslim & Ibn Abi Shaibah (12/110/2). It is given in Irwaa' (no. 8)
 Abu Daawood & Haakim, who declared it saheeh and Dhahabi agreed.
 It is thus in most of the narrations; in some, it is wa ana min al-muslimeen ("I am one of the Muslims"). It is likely that this is because of the mistake of one of the narrators, and other evidence points to that, so the worshipper should say: wa ana awwal-ul-muslimeen ("I am the first of the Muslims"). There is nothing wrong with that, contrary to what some people say under the impression that this means "I am the first person who has this quality, while the rest of the people do not." But it is not so; this phrase actually represents competing to fulfil orders - similar to this is,
"Say: if the Merciful God has a son, then I am the first of the worshippers." (Zukhruf 43:81)
And the saying of Moosa (عليه السلام),
"and I am the first of the believers." (A`raaf 7:143)
 Azhari said: i.e. `I do not worship anything other than You.'
 labbaik: I am firmly & continually present in Your obedience; sa`daik: extremely happy under Your order and devoutly following the deen which You have chosen.
 i.e. Evil cannot be traced back to Allaah because there is nothing bad in His actions, for they are all good, ranging from justice to grace to wisdom, all of which are good with no bad in them. But evil is evil because it cannot be traced back to Allaah. Ibn al-Qayyim - (رحمه الله) - said:
"He is the Creator of good and evil, but the evil exists in some of His creatures, not in His act of creating nor in His actions. Hence the Exalted is cleared of any dhulm, which is fundamentally to put something in other than its proper place. He does not put anything except in its suitable place, so that is all good. But evil is to put something in other than its proper place: when it is put in its proper place it is not evil, so be sure that evil is not from Him. ...But if it is said: 'Why did He create something which is evil?' I would say: 'He did the creating, and His action is good not evil, for creation and action is with Allaah, and it is impossible for evil to be with, or attributed to, Allaah. Anything evil in the created cannot be traced back to Allaah, but His actions and His creation can be attributed to Him, so they are good.'"
The rest of this important discussion as well as its conclusion is to be found in his book Shifaa' al-`Aleel fi Masaa'il al-Qadaa' wal-Qadr wat-Ta`leel (pp. 178-206).
 Muslim, Abu `Awaanah, Abu Daawood, Nasaa'i, Ibn Hibbaan, Ahmad, Shaafi'i & Tabaraani; those who specify it to optional prayers are mistaken.
 Nasaa'i with a saheeh isnaad.
 Nasaa'i & Daaraqutni with a saheeh isnaad.
 i.e I glorify You, meaning I consider You totally free from any deficiency.
 i.e. we are submerged in Your praise.
 i.e. the blessings of Your Name are great, for great good springs from the remembrance of Your Name.
 i.e. Your Glory and Might.
 Abu Daawood & Haakim, who declared it saheeh and Dhahabi agreed. `Uqaili said (p. 103): "this has been narrated via several routes with good isnaads." It is given in Irwaa' (no. 341) Transmitted by Ibn Mandah in At-Tawheed (123/2) with a saheeh isnaad & Nasaa'i in al-Yawm wal-Laylah as mawqoof and marfoo`, as in Jaami` al-Masaaneed of Ibn Katheer (vol. 3 part 2 p. 235/2)
 Abu Daawood & Tahaawi with a hasan isnaad.
 Muslim & Abu `Awaanah; declared saheeh by Tirmidhi. Abu Nu`aim also narrated it in Akhbaar Isbahaan (1/210) from Jubair ibn Mut`am who heard the Prophet (صلى الله علیه وسلم) saying it in voluntary prayer.
 Muslim & Abu `Awaanah.
 i.e. You are the Giver of Light to them, and those in them are guided by You.
 i.e. the Protector and the constant Watcher over them.
 haqq: truth, reality.
 Bukhaari , Muslim, Abu `Awaanah, Abu Daawood, Ibn Nasr & Daarimi.
 Although that clearly does not rule out using them in the obligatory prayers also, except for the imaam, so that he does not prolong the prayer for the followers.
 Muslim & Abu `Awaanah.
 Ahmad, Ibn Abi Shaibah (12/119/2), Abu Daawood & Tabaraani in Mu`jam al-Awsat (62/2) with one isnaad saheeh, and another hasan.
 Tayaalisi & Abu Daawood with a saheeh isnaad.