How can I overcome a bad habit?
A bad habit is usually connected to wrong beliefs and attitudes. In wanting them removed sometimes we have the wrong motive!
We should not want to change a habit only because it is embarrassing, expensive, unhealthy, or makes us feel guilty—
Rather we should want to walk closer to the Lord and desire God’s greater purpose for our life to be fulfilled. Until we deal with the underlying wrong beliefs that weaken our resistance to the bad habit, we will have only limited success in overcoming it.
The Christian must see that bad habits are ultimately spiritual issues. We must not hesitate to call them sins.
And we need to realize that the means of deliverence (chiefly the Word of God and prayer) are essential for overcoming such habits.
We are responsible for our own sin–including those sins “which so easily beset us.” The fact that we do something wrong habitually does not relieve us of responsibility. On the contrary, it may make the sin all the worse. So we must take personal responsibility for our own habits and not shrink from calling them sin.
Sinful habits are not insurmountable problems for the Christian. After all, the Holy Spirit indwells us and is working to conform us to the image of Christ. And if God be for us, who can be against us? (Romans 8:31)
Furthermore, Galatians 5:16 says This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh.
And 1 Corinthians 10:13 says There hath no temptation taken you but such as is common to man: but God is faithful, who will not suffer you to be tempted above that ye are able; but will with the temptation also make a way to escape, that ye may be able to bear it.
If we make use of the resources provided by God through His Spirit and His Word, we can attack any habit knowing that we can win.
Let me make some practical suggestions for overcoming bad habits that I think you will find helpful.
Over-Coming Bad Habits
First of all, remember that sin begins in the mind.
James 1:14-15 say:
“But every man is tempted, when he is drawn away of his own lust, and enticed.  Then when lust hath conceived, it bringeth forth sin: and sin, when it is finished, bringeth forth death.”
The person who steals first thinks about the thing he wants. He then thinks of a plan for getting it. After he has schemed in his mind, he takes it. He could have stopped the sin in his mind before it became completed in his action.
That’s why Scripture commands us to renew our minds (Romans 12:2), to think about good things (Philippians 4:8), and to meditate on the Word (Psalm 1:2), and to cast down evil imaginations (2 Cor. 10:5).
Secondly, defeating a habit also requires changes in lifestyle.
We are to make no provision for the flesh (Romans 13:14). The person who wants to stop smoking should throw away all his cigarettes and not buy any more;
The person struggling with sexual sin should get rid of any suggestive materials in his possession. Avoid the company of those who have the same problem, and avoid the places and circumstances which tempt you. 1 Cor. 15:33 Be not deceived: evil communications corrupt good manners.
Finally, don’t try to battle a bad habit alone.
Develop relationships with more mature Christians who will encourage and support you and also make you accountable Galatians 6:2 Bear ye one another’s burdens, and so fulfil the law of Christ.
Spend time in prayer with them. Ask them to “check up on you” regularly, and be honest about your failures James 5:16 Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much.
Biblical change is not just turning away from sin; it is turning toward righteousness.
The person who lies must speak the truth Ephes. 4:25 Wherefore putting away lying, speak every man truth with his neighbour: for we are members one of another.
The one who steals must not only stop stealing, he must work and give to others Ephes. 4:28 Let him that stole steal no more: but rather let him labour, working with his hands the thing which is good, that he may have to give to him that needeth.
The one whose language is unwholesome must learn to edify others Ephes. 4:29 Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.
Start doing what is right. The good habits you build will replace the sinful ones.