1- Sincerely feel regretful and beg Allah to forgive you
2- Do Ghusl al-Tawbah and pray two rak’as and ask Allah to forgive you
3- Pray for those people whom you have wronged and pay sadaqa on their behalf
4- Go to the Ziyarah of Imam Hussain (a) when you are able to. In the meantime, read Ziyarah Ashura everyday.
5- Everyday do istighfaar 70 times