Arouse your concentration and remove all disturbing thoughts from your mind, so that when you pray, your thoughts will be pure.

If you were speaking to an earthly king, who is here today and tomorrow in the grave, you would be careful with your words, concentrating on each one, lest you say something wrong.  When you pray, you are speaking before the King of kings, the Blessed Holy One.  You must concentrate all the more.  God probes all thoughts, and before Him, thought is the same as speech. ~ R’ Yaakov Ben Asher (1270-1343), Tur, Orach Chaim 98

Before you begin to daven each day, take a few moments to meditate on this idea, and see the effect it has on your davening.