In today's Office of Readings, St. Leo the Great gets right to the heart of Lent: give up sin.
He says that the main point of this season is that "the whole Church rejoices in the forgiveness of sins." To have our sins forgiven is truly a cause for joy. What a relief to have that burden lifted, the burden of our sins.
Other Lenten practices like fasting are meant to help us give up sin. Conversion from sin is an ongoing process. Even after we commit our life to the Lord, we still have to struggle against sin, not big sins perhaps, but the smaller ones that can cling to us. Maybe it's a habit of gossip, or of making cutting remarks, or laziness, or some over-indulgence.
A good Lenten practice would be to identify one of those sins that trip us up more and make an effort to root it out of our lives. That will make us more open to grace and able to receive God's love.