I am quite an amateur in the now famous field of the Power of Intention. When I first heard about The Secret, I questioned whether all these experts who manage to bend the universe with their mental power really understood the origin of their desires. After all, aren't you running the risk that you are just on a magnificent ego power trip (see Willpower, 11/12/07) Meanwhile I do understand that mental manifestation has to become part of our repertoire as we wander along our spiritual path; since we are God's co-creators, the universe is likely to ask us from time to time to move a few mountains on our path.
From what I understand, the three forces at work are quite straightforward. You have to align your soul, your consciousness, and your subconsciousness and the universe becomes your oyster. Actually, discovering the soul part almost seems to be the simpler problem; after all, that's what our spiritual journey is all about. I still would argue that you have to discover your soul first before you become a metaphysical magician: "Seek ye first the kingdom of Heaven, then shall all things be added unto thee".
The force that I don't understand well -for obvious reasons- is the subconscious. How do you make sure that our subconscious doesn't undermine what our soul and conscious will want to manifest together. Joshua David Stone claims in Soul Psychology: Keys to Ascension that it takes 21 days to cement a new habit into our subconscious. The word habit implies that there is action involved, right? Can you heal yourself by telling yourself that you are healthy each day, but you obviously don't really believe it given that you are sick? Perhaps we should tackle the subconscious the way an athlete does when he gets ready for a season. You start at a certain level of fitness and build physical and mental strength every day until you literally explode during the playoffs. If you are telling yourself every day that you are better than the day before at whatever you want to accomplish and follow this affirmation up with the necessary actions, you should be able to imprint this idea into your subconscious as well. The Power of Intention should make your personal growth rate exponential in this case.