Magick is a process of change set forth by an individual and because of that in my understanding it has four aspects that specifically make it work. though there are other things to consider when going through the process of casting magick these are the four basic variables which must be present and understood for any form of magick to be brought about.
Intention is what is intended to be brought forth.
Intent is what you want to bring forth through your manifestation. This is your goal, and what you want to accomplish. This understanding is brought into magickal workings in order to be used as a focal point in order to target your desire, and to set forth your will upon it through your actions.
Will is the push to make that intention happen.
Your will is the power that pushes you towards your intention. It is the fuel and the energy that allows your magick to move forward into manifestation. Your will be charged, focused and brought forth through many different means, and will be released in order to manifest your desires. Willing your intention to come about do to the use of power, and the actions in what you do.
Power is the force behind the push.
In magickal working this can be brought through your own personal power, or the power of another entity, or construct. Such as spirits, and deities that you have called forth, or construct such as crystals, herbs, and other objects that have metaphysical properties that are in line with your intention. All of this builds up your power towards your desire, so that your will can be able to be released through your action to bring forth your intention.
action is the thing that starts the push.
The action is the final step that releases your will, so that it will be able to go out in order to manifest your intention. this is the ritual, or working itself, and is the crescendo in point of realization between your will, and intention that leads to manifestation. It is the first action which brings forth the movement of the magick, and allows your will to start doing when it needs to in order to bring for it your intention. This act can be pretty much anything as long as it signifies your will to start working in the world.