How to Improve Our Prayers and Ourselves
The Messenger ﷺ said:
Remember death during your prayer, for indeed a man, when he remembers death during his prayer, is more likely to perform his prayer well; and pray the prayer of a man who does not think that he will [get to] pray any other prayer other than [that one]; and beware of every matter for which excuses must be made.
Rated ḥasan [good] by Al-Albānī, Al-Silsilah Al-Ṣaḥīḥah (1421).