While performing ablution or taking a bath one should start from the right side of the body

Sahih al-Bukhari · Book 4 · Hadith 167

حَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنَا خَالِدٌ، عَنْ حَفْصَةَ بِنْتِ سِيرِينَ، عَنْ أُمِّ عَطِيَّةَ، قَالَتْ قَالَ النَّبِيُّ صلى الله عليه وسلم لَهُنَّ فِي غُسْلِ ابْنَتِهِ ‏"‏ ابْدَأْنَ بِمَيَامِنِهَا وَمَوَاضِعِ الْوُضُوءِ مِنْهَا ‏"‏‏.‏

Narrated Um-`Atiya: That the Prophet (ﷺ) at the time of washing his deceased daughter had said to them, "Start from the right side beginning with those parts which are washed in ablution."

Sahih al-Bukhari · Book 4 · Hadith 168

حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، قَالَ حَدَّثَنَا شُعْبَةُ، قَالَ أَخْبَرَنِي أَشْعَثُ بْنُ سُلَيْمٍ، قَالَ سَمِعْتُ أَبِي، عَنْ مَسْرُوقٍ، عَنْ عَائِشَةَ، قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم يُعْجِبُهُ التَّيَمُّنُ فِي تَنَعُّلِهِ وَتَرَجُّلِهِ وَطُهُورِهِ وَفِي شَأْنِهِ كُلِّهِ‏.‏

Narrated `Aisha: The Prophet (ﷺ) used to like to start from the right side on wearing shoes, combing his hair and cleaning or washing himself and on doing anything else.