In Reformed Theology what mechanisms and practices does God provide a believer to help fight temptation?

The problem here is misunderstanding what the grace of God is. I will not go into any Pentecostal/Charismatic views of that but confine myself to what may fairly be viewed as representing, or agreeing with Reformed theology regarding grace:

“This Life [of Christ] has to be received and then lived out. Once we get up-and-running and begin to mature in this Life, there will be time for fine-tuning matters of doctrine and settling disputes. What I have tried to do here is to indicate how the grace of God gets us up-and-running in Life, and then to explain the basic ideas about how to live this Life in full bloom… The Christian life is an entire life of grace… We are going to look at grace as the loving provision of God that shows us how to conduct ourselves both in the Church, and in the world at large. To do this, we will seek to identify the presence and purpose of grace within many experiences common to Christians, however much we may think that these experiences are bereft of grace… Grace, then, is “God coming down to move people to places of well-being.” Explaining The Grace of God by Charles Strohmer, pp 6, 8, 11 (Sovereign World, 1993)

Then he compares the controversy of two extreme positions regarding obedience and disobedience that Christians sometimes swing into:

“Some Christians turn their obedience into a legalism by which they feel that they obtain God’s grace… It may be because of this that other Christians swing to the opposite extreme. Indifference to obedience leads them into a loose moral and ethical lifestyle in which they feel that grace is theirs no matter what they do… Now a key for living restfully with this tension may be in seeing that obedience and grace, like humility and grace, have an intimacy between them. That is to say there is a responsibility implied in the receiving of grace. Therefore, whenever God initiates something in my life I have a responsibility to follow through on it. In other words, God’s grace carries an obligation to obey. Or, if we look at it from another direction, we could say that because God’s commands are gracious (that is, for our well-being) we would be foolish not to obey.” (Ibid. p 28)

He then deals with our human weakness, or sometimes it’s our indecision, but the point is that when we work together with God in trying to do what we know he has called us to do (or not to do), we know that his grace is sufficient, and actively rest on that, not our own efforts or feelings or views. Sadly, some Christians vacillate in shocking spiritual confusion because they are not seeking to live according to “the mind of Christ” that is given to all who have “Christ in them, the hope of glory”. They are reluctant to turn their backs on the pleasures of worldly living, or (if they think it depends on their will-power and work instead of relying the grace of God) they find their will-power is no match for devilish temptations.

I was going to quote from Reformed writer A.W. Tozer when I noticed that Strohmer points to him:

“A.W. Tozer, an insightful Christian minister, wrote that the whole purpose of God in redemption is to make us holy and restore us to the image of God. Here is the grace of God at work within the soul, transforming the inner man, the interior life, into Christlikeness. This moves the ongoing disciple into increasing levels or degrees of inner well-being. One's character becomes more like Jesus Christ’s.” (Ibid. p 53)

This is explained more fully by Tozer who has written:

“Faith and morals are two sides of the same coin. Indeed, the very essence of faith is moral. Any professed faith in Christ as personal Saviour that does not bring the life under plenary obedience to Christ as Lord is inadequate and must betray its victim at the last. The man that believes will obey. God gives faith to the obedient heart only. Where real repentance is, there is obedience. To escape the error of salvation by works we have fallen into the opposite error of salvation without obedience… A whole new generation of Christians has come up believing that it is possible to “accept” Christ without forsaking the world.” Gems From Tozer, pp 50-51 (Christian Publications Inc, 1979)

That brings me back to my starting point – misunderstanding what God’s grace is. The four points Pentecostals might list betray such misunderstanding, just as does the sad fact of a person who does not appear to have progressed in overcoming sins. Christians can stand and grow in the grace of God when they have the biblical view of it. Evidence of the grace of God at work, moving a person on to become more and more Christlike shows an obedient heart, a responsible attitude, and a loathing of going the way of the world, resulting in depending on the grace of God to overcome. He never deprives such a believer of grace sufficient to be more like Christ, but beware of those who would judge others and compare themselves more favourably. That indicates pride, not the humility that is a hallmark of the person led by grace.