As a typical and easy prayer to recite, the Three Hail Marys comes highly recommended.
Times for sheer devotion include the morning and around sunset, as per traditions that have developed in Europe.
But the Three Hail Marys can be offered for basically any petition, any prayer, any problem.
It's quick, easy, and effective practice that comes highly recommended from me.
According to St. Gertrude (1256–1301),
the Blessed Virgin Mary promised the following:
"To any soul who faithfully prays the Three Hail Marys,
I will appear at the hour of death i
n a splendor of beauty so extraordinary
that it will fill the soul with heavenly consolation."