رَبَّنَا آتِنَا فِي الدُّنْيَا حَسَنَةً وَفِي الْآخِرَةِ حَسَنَةً وَقِنَا عَذَابَ النَّارِ
Rabbana atina fid-dunya hasanatan wa fil-akhirati hasanatan wa qina 'adhaaban-nar
Ya Tuhan kami, berilah kami kebaikan di dunia dan kebaikan di akhirat, dan peliharalah kami daripada azab neraka.
Comprehensive dua that can be said before salam or anytime
This was the most frequent dua of the Prophet (PBUH), asking for good in both worlds.