Istighfar, or seeking forgiveness, both prevents hardship and is a means of relieving hardship. Sh. Omar Suleiman describes one of the best du'as to make for seeking Allah's forgiveness.

اللهم أنت ربي لا إله إلا أنت، خلقتني وأنا عبدك، وأنا على عهدك ووعدك ما استطعت، أعوذ بك من شر ما صنعت، أبوء لك بنعمتك علي، وأبوء بذنبي فاغفر لي فإنه لا يغفر الذنوب إلا أنت

Allahumma anta Rabbi la ilaha illa anta, khalaqtani wa ana abduka, wa ana 'ala ahdika wa wa'dika mastata'tu, A'udhu bika min sharri ma sana'tu, abu'u Laka bini'matika 'alaiya, wa Abu'u bidhanbi faghfirli fa-innahu la yaghfiru adhdhunuba illa anta.

O Allah! You are my Lord! None has the right to be worshiped but You. You created me and I am Your slave, and I am faithful to my covenant and my promise as much as I can. I seek refuge with You from all the evil I have done. I acknowledge before You all the blessings You have bestowed upon me, and I confess to You all my sins. So I entreat You to forgive my sins, for nobody can forgive sins except You.