Prayer to me is foremost a privilege that is extended us by virtue of our patternship as image-bearers. We speak to Him (as limited participants in relation to His vast intellect) as beings nevertheless capable of the desire for intended outcomes - short-sighted, weak and ineffectual as they may be. We wish for this and that or the other thing to occur, for it seems right and proper to us that they come to pass within the lives of those who serve Him. Yet it is paramount for us to realize that our intentions can never change the events that are divinely set to occur, for He is completely sovereign over each and every event that plays out in time. Mind you, it is certainly not out of place to raise a sick friend before God for healing, but only upon the grounds that it serve to glorify God in some way or otherwise advance His purposes here on earth. It could even be so that the power of prayer itself is attested to in a most visible way! However, it is God who chooses and effects even the individual path of each leaf that flutters to the ground at they are shed by the tree, just as the total number changes every time we loose one of our hairs. The point is, God is mindful of even the least (to us inconsequential) aspect of His creation - and that to the minutest detail. As such, He does not need us in order to govern, yet graciously allows us the privilege to participate in the process. He does hear our requests, and it is an important act of faith and trust that we would wait upon Him.
Hence effectual prayer is essentially a petition for alignment between two wills - that between man and God. And I find that the nature and character of your prayers will change dramatically as this truth begins to set in. The goal is to align your specific petition to the will of God in any particular area, for this becomes the sole way to play any supporting role in the affairs of how the world is destined to go. Lifted in symmetry to the intent of God, the power of this kind of prayer knows no limits in its effectiveness, and in the end it is a spiritually mature mind to realize that we all want whatever God wants as well. To put it another way, God's ears are always attentive to the prayers of those who seek His ultimate glory, and it is an amazing thing even to consider that He graciously grants us the right of testimony (in the act of petition) in this regard. Therefore, it is both right and good that we come to the Lord in presentation of our requests, for it acknowledges His ultimate power to effect outcomes.
Limited in both time and space however, we do not possess the necessary qualifications in order to sit at his council, and we are only given the profound permission to align our petitions with His sovereign will. It is a thing to be closely guarded, cultivated and carefully fostered by the Spirit within us as we are being continually conformed (inwardly) to His likeness. Here, we gradually learn to raise our concerns in appeal to His essential character as they serve to govern over His decisions. In short, in order to play any real part in the determinant order of things, we would do well to touch upon either His holiness or His great love when engaged in the act of petition. Hence a sick friend healed solely for selfish reasons (or even for their own sake) is a poor way to raise a legitimate concern unto a Person who lies at the virtual epicenter of the spiritual realm - it must be done to the credit of His love. Health, longevity and wealth are similarly devoid of merit in and of themselves, for He is to be the object of glory above all else.
As an example of what I consider to be ineffectual prayer, I heard recently a petition for "peace and love" to reign in our country for the coming new year. Written on a general prayer request card for the pastor to reiterate in the upcoming corporate prayer, many a churchgoer might be tempted to utter similar words in their private prayer life as well. After all, who wouldn't want these very things to describe the situation in our country, right? Well, outside the way His church naturally effects these things as the gospel message forges its path in the midst of an adulterous and wicked generation, this petition lies rather weak and powerless. In fact, I suspect that it was directed chiefly at the current political situation that has served to deeply divide our country. Now, to be sure, it made direct appeal to His love and the peace that ensues from this primal aspect of His character, yet it makes no effort to acknowledge that His renown is most often forged in the press of intense conflict, especially as it is reflected in the (un)civil discourse found in current politics. Indeed, peace and love can never be used to describe the situation between Satan and the purposes of God, and any petition toward the affairs of our nation must make room for this spiritual reality. A much better way to make appeal in this regard would be to pray that the warriors of this generation accomplish the will of God as their public testimony is given in witness to the truth found in scripture. That would be an example of effective prayer.