Taariq al-Ashja'ee (radhi-yAllaahu 'anhu) said: When someone would embrace Islaam, The Prophet (sal-Allaahu 'alayhe wa sallam) would teach him how to perform prayer and then order him to supplicate with the following words:

اللَّهُمَّ اغْفِرِ لِي، وَارْحَمْنِي، وَاهْدِنِي، وَعَافِنِي وَارْزُقْنِي

O Allaah, forgive me, have mercy upon me, guide me, give me health and grant me sustenance.

Allaahummaghfir lee, warhamnee, wahdinee, wa 'aafinee warzuqnee.

Muslim 4/2073