When I was preparing to go home from my mission, our mission president called all the returning missionaries in and gave them this counsel to live by as we return home, and start preparing for marriage. Some of these change slightly when you get married, but the principles remain the same.
1st. Daily prayer morning and night.
He told us that they've found when someone falls off the train this is the first step they took. They stopped praying. Never forget to pray in the morning, and at night.
Praying is very important. Without prayer it is impossible to repent. Without repentance our soul will get weak, and then we cannot enjoy the full Gift of the Holy Ghost. Make sure you are not just "saying" your prayers, but having real communication with our Father.
2nd. Daily scripture study.