Indeed, the struggle to remove extraneous thoughts from one’s mind and focus on the words of the prayers is immense.
And this stems from the fact that the goal is uncompromising: all thoughts other than meditating on Hashem’s greatness and the meaning of the words one is reading must be rejected. This even means that one should not read the words of Tefillah with one’s lips while reflecting in the back of one’s mind on topics in Torah. This is the reason that before Tefillah one should not study pilpul, intensive Talmudic analysis, but only practical halachic rulings. After studying pilpul, the mind is still excitedly grappling with complex ideas, and so even without consciously intent, one’s thoughts are prone to drift off from Tefillah to one’s studies. In contrast, practical halachic rulings do not engross the person, and so we are not concerned that such study will bring on stray thoughts during Tefillah.
If even thoughts of Torah should be rejected during Tefillah, one should surely reject thoughts of the mundane. This includes dispelling otherwise permitted and constructive thoughts, such as thoughts of one’s livelihood. It is especially difficult to clear one’s mind if one is emotionally distraught from hardship in some area of one’s personal life (may Hashem spare us).
This is also the reason that during Tefillah one should keep looking inside the Siddur at all times, for allowing one’s gaze to wander around Shul can trigger distracting thoughts. Moreover, since “letters illuminate,” gazing at the printed words helps focus one’s concentration.
In the case of Shacharis, we know that various specific preparations are prescribed with the goal of fostering the appropriate mental state (see here). So instead let us discuss Minchah and Maariv, for it is not written (as far as I am aware) that one ought to make a point of preparing for these Tefillos through a session of Torah study and hisbonenus (contemplation of Hashem’s greatness). (The reason for this is that the preparations for Shacharis are said to extend throughout the day, to Minchah and Maariv.) Nevertheless, this does not mean that it is acceptable to rush in from one’s car such that one enters the Shul at the exact moment that the Minyan begins (and that’s in a good scenario).
This is reflected in the Talmudic ruling: “Rav Chisda said: [When entering Shul] one should always enter a measure of two doors-worth and then pray” (Berachos 8a). One explanation of this is that one should wait briefly before starting to read the words of Tefillah.
During this time one should make a conscious effort to mentally cast aside all the aspects of day-to-day life that were preoccupying one until then, in order to enter the calm, lucid state of mind conducive to proper concentration. In Yiddish this process of transition is known as “shtelen zich davvenen.”
So instead of arriving at the 2 pm Minyan for Minchah at 2:00:39 short of breath and zipping through Ashrei in order to make it in time to answer Kaddish, do yourself a favor and come just five minutes earlier. Relax a bit, say Korbanos slowly, glance in a sefer, put a coin in the pushkeh, and remind yourself simply about what you are about to do—the purpose of all the words you are about to read: You are about to be granted the opportunity to stand directly before Hashem and praise Him, plead that He grant your requests for sustenance, and then thank Him for His kindness.
It will make all the difference.
Adapted from Kuntres HaTefillah, p. 23.