No matter what you've been taught the Catholic Church is not so much about rules and regulations but about a passionate loving relationship between Creator and creature. To be honest it seems like too many Catholics have become comfortable with the "rules and regulations" story. It easier to trade heavenly reward for following rules than to enter in to an authentic , passionate relationship with the creator.
All sin matters and Confession is not just something you need to do once a year. We are giving ourselves too much of a break on sin. Sin is real and it has consequences for this life and the next. It affects our intimacy with God. We are all sinners so lets face the facts and work on those things hurting our neighbors and keeping us from greater intimacy with God. Once we recognize this fact we fall in love with confession. I am so thankful my God has set up such a beautiful sacrament for me, a great sinner, to go to for mercy.
The way we receive Communion says a lot about the state of our soul. I wish we could take a video of what communion looks like at an average parish and show it to them. Greeting people, talking, checking phones, hands swinging and the like have become the norm. Many people receive communion like they are taking candy. If we teach our children one thing it should be how to "Communicate" correctly. Contemplate the gravity of what we are doing on the way up to communion and let our outward actions show the disposition of our soul.
Learn the Gospel. Most Catholics do not know the basic Gospel story. You just can't know Jesus without entering deeply into the Gospel story. If you are really moving you can read a Gospel in an hour. Commit your self to reading a Gospel a week.
A relationship involves communication, you need to start praying. Our relationship with Jesus does not end with sunday mass. Catholics must have a personal daily relationship with Jesus. It doesn't need to be strenuous or profound but it does need to happen.
Despite what every "CCD" book tells you Baptism does not make you an "Intentional Disciple." Being a disciple means forming your entire life around your relationship with God. It means asking God what he wants from every moment of our lives. Discipleship is a radical life of relationship and change.
Evangelization is the common duty of all the baptized. If you are a Catholic then necessarily you must evangelize. There is no question about it. You will not keep your faith without sharing it.
If you want to get the most out of the Faith you are gonna need to learn some basic theology. People need to learn the basics of the seven sacraments. You need to know what it means to be a Priest, what it means to be baptized and confirmed, what the Mass really is. This will change the way you live.
If you disagree with a teaching of the Church you have a duty to learn why the Church teaches it. So many catholics out there disagree with the church on something but they don't ever look into the "why" behind the rule. You can't just assume you are right about everything. You have to give your best effort to understand the teaching you disagree with.
They'll know we are Christians by our love. We must build communities of love in our parish. We are called to community. This is a hefty call because community requires sacrifice for others. We must continually encounter each other in love.