Repentance is an absolute requirement for all people to allow them return to Heavenly Father's presence after death, and become a god themselves. To repent is more than just to acknowledge and confess your sins, it is to feel sincere sorrow that what you have done is vile and contemptible. It is to make restitution and pledge not to commit those or any other sins from that point forward. Jesus rejoices when we repent.
Part of repentance is doing all you can do to right whatever wrongs you have committed. If your sin affected someone else, you must confess your sin to them, offer sincere apology, and make restitution. If you lied, make the truth known. If you gossiped or slandered another's reputation, do all you can to restore their good name. If you stole from someone, return what was taken.
In addition to confessing all our sins to Jesus, you must confess all serious sins that might affect your standing in the Church to the proper priesthood authority. This includes such sins as the sale or use of illegal drugs, abuse of a spouse or child, or violations of chastity such as fornication, adultery, or homosexual relations.
To be truly repentant, you must maintain a permanent, unyielding resolve never to repeat the sin you have committed, and you must commit to obeying all of God's commandments. If you repent for adultery, but still drink alcohol and curse, you are not truly repentant. If you repent for breaking the Sabbath, but neglect to pay your tithes, you are not truly repentant. True repentance must cover all areas of your life.
Another vital part of repentance is to forgive all others. It is easy to become angry, bitter, or vengeful when someone wrongs you, especially if it was intentional, but you should abandon such feelings. Jesus has commanded that you should love your enemies, bless those who curse you, and do good to those who hate you. When you are wronged, your response should be "Let God judge between me and thee, but as for me, I will forgive."
Do not procrastinate your repentance, for the longer you wait, the weaker your ability to repent becomes. Some people believe they should put off repenting for their sins until just before visiting a temple, just before going off to serve on a mission, or until they are on their deathbed. But such behavior mocks the atonement of Jesus Christ and invites Satan's influence over your life.