1. Realize that Satan is more powerful than you are.
You cannot hope to overcome Satan's attacks on your own. He is a "roaring lion...seeking whom he may devour" (1 Pet. 5:8). He has defeated stronger people than you. It is clear in Scripture that the only hope we have against him is by submitting to God.
"Submit yourselves therefore to God. Resist the devil, and he will flee from you." - James 4:7
"Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world." - 1 John 4:4
2. Pray daily for God's help against the enemy.
"And he said unto them, when ye pray say,... And lead us not into temptation; but deliver us from [the] evil [one]." - Luke 11:2-4
3. Work constantly at amturing in every area of your Christian life. (Read Ephesians 6:10-18.)
4. Know your Bible very well. Every time the Lord Jesus Christ was tempted by the Devil, He responded by quoting Scripture. But remember that Satan also quoted from the Bible. The problem with Satan's quoting of Scripture was his taking the verse out of context, misapplying it, and contradicting other Scripture with a false interpretation. You must know your Bible and know it well.
"Thy word have I hid in mine heart, that I might not sin against thee." - Ps. 119:11
5. Guard against your areas of weakness and be sensitive to the circumstances which brings temptation to you.
"A prudent man forseeth the evil, and hideth himself: but the simple pass on, and are punished." - Prov. 22:3
6. Ask God for the power of the Holy Spirit in your life.
"And Jesus being full of the Holy Ghost... was led by the Spirit into the wilderness, Being forty days tempted of the devil." - Luke 4:1-2