Whatever you pay attention to will dominate your life and what you attract is what you believe. If you pay attention to the devil he will dominate your life and if you focus on God He will dominate your life.
Many Christians pay attention to things like the past mistakes. Condemnation is the root of your problems because it makes you lose confidence. You are constantly thinking that God is angry at you for your mistakes but you need to ask yourself if you serve a monster or a Father?
You serve a loving Father who cannot condemn you. God is not angry with you. Every possible punishment He could have given you has long been paid for once and for all on the Cross. Through Jesus Christ, you were forgiven and given a fresh start. Stop being mad at yourself. God is on your side!
Through Jesus Christ you receive the abundance of grace and the gift of righteousness. You must develop a righteousness-consciousness and move away from a sin-consciousness. Stop condemnaing yourself. Even when you miss it, declare that you are the righteousness of God, forgiven and redeemed! You are a child of God. No more condemnation!