Start with this Du'a
Against bad omens
اللَّهُمَّ لاَ طَيْرَ إِلاَّ طَيْرُكَ، وَلاَ خَيْرَ إِلاَّ خَيْرُكَ، وَلاَ إِلَهَ غَيْرُكَ
Allahumma la tayra illa tayruk, wa la khayra illa khayruk, wa la ilaha ghayruk.
“O Allah, there is no omen except what You decree, no good except Your good, and there is no god besides You.”
Musnad Ahmad 7045 (hasan)
The Prophet ﷺ taught this as the expiation for anyone who lets a superstitious omen turn them away from what they meant to do.