Recently a friend of mine made an innocent mistake, and I reacted with a very rude attitude. Before I apologized, there was stiffness in our communication because I had not settled the offense between us. However, after I admitted my fault we spoke normally. This made me think about how Jesus views a person who prays to Him without first repenting of sin. Think about it, could you wrong someone and then turn around and speak to them like nothing happened? Would you really just assume they forgave you? Well then how could you approach God in that manner? How can you expect Him to forgive your sin if you disregard it?
Each time you pray, first examine your ways and confess your sins to Christ. For example, were you rude to someone earlier that day? Did you have a lustful thought? Did you lose your temper while driving?
Repentance means confessing your sin/fault to Christ and then forsaking that sin/fault. Also ask the Holy Spirit to reveal any sins that you are unaware of. Living a lifestyle of repentance will help you maintain a close relationship with Jesus and make your prayers effective. The Bible says that God does not hear sinners when they pray. If you have specific sin which you frequently struggle with, pray daily for Christ to help in those areas. You can also pray and fast to be set free from specific sins. You may not always see change overnight but Christ will be faithful to help you as you persist.
Now we know that God heareth not sinners: but if any man be a worshipper of God, and doeth his will, him he heareth.
If I regard iniquity in my heart, the Lord will not hear me: