rituals, symbols, actions, gestures and language
in an attempt to achieve some kind of spiritual growth. Those who practice magic use these elements to achieve inner peace, accomplish goals, connect to the world, and seek something beyond themselves.
The rituals of magic are often practiced either in solitude or secrecy, which is one of the reasons magic has so often been looked at with skepticism, criticism and even fear throughout the ages.
While most practitioners of magic will claim that their intentions are pure and benevolent rather than harmful and hateful, there is an element of magic which is undoubtedly meant for the darker spiritual elements. This is often referred to as "sorcery."
The word "magic" is rarely if ever used to describe as a religion; the form of magic which is referred to as a religion is called "Wicca." Magic is referred to most often as an art, and it is a practice rather than a belief system.
A religion is a belief system. This system can look quite different depending on the denomination or group which practices it, but each religion is comprised of some basic tenets and doctrines, practices, symbols, and leadership structures.
If religion were easily identifiable as one thing, all religions would be the same. The core of every religion--its deeply held beliefs--is at least a little different than every other religion. How the followers of that religion live that out, in terms of its rituals, symbols and actions, might also be quite different.
Obviously magic is a practice rather than a religion, though certainly it is possible for a religion to practice or use magic as part of its religious rituals.
Of course some people do use religion to influence outcomes; however, that can be said of many other things in this world, too. Religious leaders have the ability to influence or manipulate their adherents using such things as fear, emotion, guilt, and power. The same is true, though, of politicians, coaches, corporate executives, parents and nearly anyone else who holds a position of power and authority over other. Large and powerful countries use their power to influence other countries, for example, and this kind of power-wielding is common in many other arenas.
The third question is a little vague, but what I think you are asking has something to do with the supernatural forces in witchcraft versus the supernatural aspects of religion. It seems to me that asking God to perform a miracle, for example, is different than casting a spell or performing a ritual in an attempt to make something happen. One is an appeal to the Creator to act on one's behalf while the other is an attempt to make nature do what one wishes. (The next level of this is asking Satan to act on one's behalf, but that is Satanism rather than magic.)
Undoubtedly it is my personal belief system which moves me to this conclusion, but it seems much more significant and effective to make a request of God through prayer than to make a request of the forces of Nature through an incantation or spell. For those who have no faith in the existence or power of God to act on man's behalf, however, asking Nature to act seems as likely or even more likely to produce a result than expecting a mythical, non-existent god to do something.