From the beginning of time, temptation to evil has been the bane of mankind's existence. Given that we have been endowed with sufficient intelligence and understanding to easily discern that to be evil is to be a curse to one's society, it is a testimony to our fallen nature that we so readily give in to temptation.
This solicitation to evil comes to all, believers and unbelievers. Without God, you are left to resist it in your own strength. While you may be successful in some areas, the tempter, Satan, has an immense bag of tricks, and all the time in the world. He will hammer away at you until he finds your weak areas, and then mercilessly attack them until you finally succumb. Those who are walking with God, however, are in a completely different position with respect to temptation. They are under His special protection, and to the degree that they allow Him to meet the temptation, they will be triumphant over every incursion of Satan.
For the believer, there are a few key points to keep in mind in dealing with temptation.
Evil thoughts will occasionally enter the mind of a Christian, seemingly out of nowhere, and then the devil will say, "See, you're evil. You've sinned. You aren't really a follower of God because you are thinking thoughts contrary to His holiness." This is a case where Satan becomes quite sanctimonious in an attempt to get you to give up on following Christ.
Recognize that while Satan has some level of access to our minds, the mere presence of an evil thought is not evidence of rebellion toward God. No, that only happens when we take such thoughts and run with them. When we do this, these thoughts, like seeds, begin to germinate, and in time they can indeed become sin. So what you must do is get rid of the thoughts immediately. Rebuke them in the name of Jesus. Call upon the Lord for protection and cleansing of your mind.
We are destroying speculations and every lofty thing raised up against the knowledge of God, and we are taking every thought captive to the obedience of Christ... (2 Corinthians 10:5)
The longer you let the thought stay in your mind, the more dangerous it is. Sadly, many Christians fail to master this very simple technique, and thus find their spiritual vitality greatly weakened through constant unnecessary conflict with Satan. Once he knows you are adamant about not prostituting your mind out to him for his evil purposes, you have removed a mighty weapon from his arsenal. We cannot begin to emphasize enough the importance of guarding your mind in this manner.
Know also that while temptations will come in many forms, you will never face anything that you cannot possibly overcome.
No temptation has overtaken you but such as is common to man; and God is faithful, who will not allow you to be tempted beyond what you are able, but with the temptation will provide the way of escape also, so that you will be able to endure it. (1 Corinthians 10:13)
The key here is to always look for the door. There is a way out, and it won't be hidden, unless you are hiding it from yourself. If you find yourself in a situation where what is happening around you is weakening your resolve, vote with your feet. Get out of there. An example of this was when the wife of Joseph's employer found him alone in the house and was determined to finally have him.
She caught him by his garment, saying, "Lie with me!" And he left his garment in her hand and fled, and went outside. (Genesis 39:12)
Another tool is the power of your own words. Make a declaratory statement as a defense against the temptation you are facing, such as, "No, God delivered me completely from cigarettes when I gave my life to Him, and I don't need them anymore."
Remember that when we pray, "And lead us not into temptation" in the Lord's Prayer (Matthew 6:9-13), it's incumbent upon us that we don't lead ourselves into temptation. Don't go places or do things that you know could entice you to sin. You must avoid these areas at all costs. Yes, other Christians may be able to do things that you cannot because our weak areas may be different than theirs. Don't worry about it. You want to make it to Heaven, right? Then use your head, and protect your heart. Watch out for the snares and avoid them.
Keep in mind that God is on your side, He is determined to see you all the way through, and He has the power to keep you in the hour of temptation. Lean on Him. Call on Him. Let Him be a wall of protection around you every hour of every day.
Now to Him who is able to keep you from stumbling, and to make you stand in the presence of His glory blameless with great joy, to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion and authority, before all time and now and forever. Amen. (Jude 1:24-25)
Scripture quotations taken from the NASB