Repentance

True repentance comes when we change both our actions and our hearts and desires. You may not want to give up some sins--that's what makes them temptations, because they seem desireable. But when you consider that anything that's a sin is designed to make you miserable, how can you rationalize committing them? How can you at least not want to change? The good news is that the more you repent, the more sense it all makes, the better you feel, and the less those old sins appeal to you. Looking back after progressing, your old sins will be repulsive to you.

Does Sinful Experience Make You a Better Person?
You've probably heard this one before: "I can resist drugs (crime, immorality, etc) better because I've been there, I know what it's like, I know what I'm talking about. I'm a better person for having gone astray and returned."

Is it true? Maybe yes and no. If they're truly repented and are now more permanently devoted to God and obedience, then apparently yes, they are better people. Is it because of sin? No, it's because of repentance and the grace of Christ. Truly repentant people do not glory in their past sins, but regret them (see 2 Nephi 3:21 "make me that I may shake at the appearance of sin", Alma 13:12 "after being sanctified by the Holy Ghost, having their garments made white, being pure and spotless before God, could not look upon sin save it were with abhorrence", Alma 29 is excellent on this).

Jacob shed a great deal of insight on this question when he taught that he and others recorded the scriptures to teach the gospel so that we "may learn with joy and not with sorrow...". Sin causes misery and pain, which must be faced to repent. Through obedience, we are given faith and strength and understanding. Through obedience, we learn with joy. Now which way would you rather learn?

How to Make Repentance Easier and More Permanant
It's easier to build desires than to fight against them. In other words, don't focus on your sins and things you dont' want to keep doing, focus on your love for God and His commandments, for the great way you feel when you obey Him, when you know He loves you, etc. Then, when those other temptations beset you, focus on how much you want to do what's right. You might even fail a few times, but humble yourself and try to come back stronger every time. Eventually, you will succeed.

Repentance is Exciting
When you decide to repent, you might see two things: the effort it will take and the happiness that will follow. Know that when you decide and act this way, God is pleased and will help you. Know that blessings await you, they're guaranteed if you keep trying and desiring to do better. Focus on this to motivate yourself.