Temptation will be an ongoing problem for believer and non-believer alike until Jesus returns and completes his victory over sin.
The first thing to note is that temptation is not sin nor is temptation a sign of weakness. Temptation becomes sin, however, if we do not deal with it properly. It is how we deal with temptation that will determine whether we fall into sin or not. So until he returns, I think the Bible gives us 3 strategies for dealing with temptation - Praying, reading & fleeing.
Praying - Jesus teaches us in the Lord’s Prayer to pray against temptation and the work of Satan [Matt 6:13]. As our heavenly Father he delights in us coming to him and answering our prayers. So we should pray that he would strengthen us against tempting and testing situations, that he would protect from tempting and trials that we cannot bear. We should pray that God would deliver us from Satan and his schemes to bring us down and undermine our faith.
Reading [the Bible] - When Jesus was tempted in the desert by Satan, Jesus response was to revert to the scriptures. He knew the Word of God and was able to use in his spiritual battle against Satan. For us, knowing the Bible helps us to know what is good, godly and right and what is wrong, ungodly and sinful. More importantly, knowing the Bible helps us to know how to deal with tempting and testing situations when we are faced with them.
Fleeing - The Bible tells us to flee from situations where we are tempted. Flee sexual immortality [1 Cor 6:18]; flee from the love of money [1 Tim 6:11] and flee evil desires of your youth [2 Tim 2:22]. We can make it hard for ourselves if we sail as close as we can to temptation and sin, trying to test our resolve or strength. Put barriers in place that mean we won’t face temptation, or at least face it less often. For example, if sexual temptation is an issue, don’t meet up 1:1 with people of opposite sex. Be proactive; put strategies in place to keep temptation at bay.
The Christian life is one of ongoing transformation as God shapes and moulds us to become more like Jesus [Rom 8:28-29]. Some things will change quickly others will be a lifelong process of obedience, perseverance and repentance. Until Jesus returns we will never be perfect, and so sin will continue to be part of the Christian experience. Galatians 5:16-26 speaks of the ongoing struggle it is to be godly.
However, the Bible assures us that Christ died for ALL our sins, and so there is forgiveness for those who are genuinely repentant and seek to follow him. [1 John 1:8-2:2; Joel 2:12]