One should recite the following duaa after salaah:
اللَّهُمَّ أَعِنِّى عَلَى ذِكْرِكَ وَشُكْرِكَ وَحُسْنِ عِبَادَتِكَ
O Allah, assist me in remembering You (at all times), being grateful to You (for Your countless bounties) and carrying out Your worship in a beautiful manner.
عن معاذ بن جبل أن رسول الله صلى الله عليه وسلم أخذ بيده وقال يا معاذ والله إنى لأحبك والله إنى لأحبك. فقال أوصيك يا معاذ لا تدعن فى دبر كل صلاة تقول اللهم أعنى على ذكرك وشكرك وحسن عبادتك (أبو داود رقم 1524)
Hazrat Muaaz bin Jabal (Radhiyallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) took hold of his hand and said: “O Muaaz, by the oath of Allah, indeed I love you (for the sake of Allah Ta’ala). By the oath of Allah, indeed I love you (for the sake of Allah Ta’ala).” He then said: “I advise you, O Muaaz, do not ever leave out reciting the following duaa after every salaah:”
اللَّهُمَّ أَعِنِّى عَلَى ذِكْرِكَ وَشُكْرِكَ وَحُسْنِ عِبَادَتِكَ