St. Ignatius spoke of the "agere contra" principle which means "to act against." It's a simple concept. When trying to overcome a particular sin, act against it, even in an exaggerated way.
For example, we fast on Ash Wednesday & Good Friday because we are acting against our tendency to over-eat and over-drink. If someone is ambitious, they can instead look for opportunities to do something good without telling anyone about it. They act against their pride & their ambitiousness in this way. If we're jealous or envious of someone, we can praise that person for the good we see in them. If we are lazy, we can focus our time & energy on a particular project.
Our greatest example of this principle is of course Jesus. The devil tempted him with all the food he could possibly enjoy, so Jesus fasts in the desert instead. The devil tempted him with power and glory, but Jesus chooses to worship God alone. The devil tempted him to put God to the test, but instead Jesus places his trust in God. Jesus always did the opposite of what he knew was sinful or selfish or against the will of God, and he often did these things in an exaggerated way. During Lent, we fast because we consume too much; we pray because we talk to God too little; we give alms because we keep too much for ourselves. What is a part of your life that is not holy? Act against it this Lent by the power & grace that God will give you.