This isn't another one of those "The road to hell is paved with..." speeches, for as we know, the road to hell is paved with tits, according to Electronic Arts...But at any rate, intention is basically the key to anything and everything that you are attempting to accomplish, both in the physical and not-so worlds. It shapes and gives form to what you are attempting to accomplish, and can, at times sabotage your entire effort. If you are angry at the time you begin, that will color you whole endeavor. If you're having "giggle fits" while trying something serious...even so. Want to test this? Put on a good standup comedian, be it Robin Williams, Bill Engvall, Eddie Griffin, etc and try to balance a bowl of water on your head...try not to spill any. Does that seem too much like a test of wills to you? Maybe because that's what it is...at first.
The idea is to allow your endeavor and your intentions to mesh into one, and then success is yours, in whatever it is that you are attempting to do. Especially in the metaphysical aspects, where what you are trying to do could completely backfire in your face. Crowley may or may not call it a Declaration, but he's full of it anyway, so his opinion doesn't count. I call it a "Surrender" of sorts, a surrender to yourself and the world around you.
It is simply to clear your mind of all distractions, inside and out. To "quiet your mind" so to speak, so that there is no thought, only self. There is no fast and easy rule or timeframe for this, but it's usually the goal of most meditation, but you are meditating on NOTHING, for to meditate on anything is to already color what you are attempting. Then, and only then, do you state, or form your intentions within yourself.
A good personal example is this: When asking someone to scry for me, this person did take the time to clear the mind and focus on the intentions, which was more or less to quiet my unease and misgivings regarding...someone. If the intent was blocked by "I'm doing this to shut him up", the results wouldn't have been clear, if at all there. Instead, the clarity of it gave a clear image almost as good as a printed picture.
That example could be used for anything. Asking for a promotion, raise, looking for work. Before beginning an important task, simply quiet your mind (followers of Bushido call this Mushin, or "no-mind"), and then focus on your intent. It is the key, and will lead you to where you are needed to go. Notice I did not say "Where you want to go".....