The Magician (I), also known as the Magus or the Juggler, is the "1st" Major Arcana, but it's still a long way from the Fool (0).
In Magician, the journey has progressed so far that the initiate now has an altar table, magical instruments representing all elements (including gold), fancy robes and a fancy garden. The initiate has come very far from the wondering bum with nothing but a backpack on his back and a flower in his hand (we'll kindly ignore the loyal dog - the most wonderful companion one can ever have, for the sake of the allegory). Very far indeed... The initiate has travelled the world, and more than that - took a leap of faith, fucked around and found out, and now s/he is able to evoke, invoke, cast and conjure to his heart content and imagination's length.
The Magus is one of the most powerful cards because it represents those who have not just been initiated into the occult arts, but those who have mastered them so much so that they are able to manipulate and shape reality around them, and others. This is the card of creators, initiates, instigators and decision-makers.
When this card comes up in a reading, especially a career or goal-related reading, you know that the outcome is going to be exactly what the asker has imagined - whether good or bad - the manifestation is coming true, and in the style of Uranus - it's something unique, otherworldly and special in all regards.
This is an omen for (mostly) positive changes, and it represents the transfiguration of reality aligned with the asker's inner world. If this card comes up in a love reading, you know that you are successful in manifesting your special person.
This Major Arcana also stands for all Cardinal signs (Aries, Cancer, Libra and Capricorn) as it represents those who initiate things, those who make the first step and do so daringly. Natives who feel strongly connected to this card are natural leaders and decision-makers. The Magician is at the forefront of creation, and what Cardinals do than create?
The Magus can also be a hint to a field in your natal chart that needs more attention (see what houses Cardinals occupy in your chart, what is happening there and what kind of transits are you having when the Magus pops up in reading in order to get more clarity).
If you're dealing in the occult, then the Magician (in its upright state) is a sign that your ritual/spell worked, and that the desired outcome is on its (cosmic) way to you. He is also warning you that you should discipline your thoughts, and let go of a manifestation if you are done with it. Clinging to the end result can have the opposite effect thanks to the vibration of the feelings you emit when you focus on what you lack, instead of feeling the success of what you wish to receive.
When the Magician shows up, you are urged to be more creative and open to opportunities, and to receiving (whatever it is that you want). This card is showing you the way, and all you need to do is visualize it.
When it comes up in an occult reading, it can be a sign that you need to cleanse and repurpose your magical tools; perhaps the time to change up your altar has come, or the time for the offering to the gods/ancestors is upon you. Try to remember when was the first time you gave an offering, and see that you do it shortly afterwards.
The Magician can easily be used in all kinds of rituals and for attracting and fortifying the desired outcome. One of the simplest spells is to place the Magician on top of the manifesto or a list of things you want, the way you want it, and to tie it all up with a golden thread, preferably when the Moon is in Aries, Sun in Cancer, Mercury in Libra and Mars in Capricorn. The best day for manifesting depends on your Almuten Figuris. As for the hour, it depends what is the nature of your desired goal.
If it is romance/love, then, of course, Venus or Moon, if it is success and achievement, then Sun, Mars or Jupiter. If it is power, then Pluto, if it is breakthrough then Uranus, if it is spirituality, then Neptune...
You can also fortify weaknesses and foul aspects or placements in your natal chart. Make sure to give indications or offerings from your body that represents the area you wish to improve, and then put the Magician on top of the appointed (and anointed) area on your natal chart. By painting your natal chart yourself, and highlighting the areas you wish to "cure"/enhance, you are making the magic (binding) stronger. But you can always just print it, of course.
The Magician is not a card for everyone, and not everyone will feel connected to it, it's somewhat a royalty of the card, as it only "gets in touch" with those who have "the touch", and are fond of easy, almost instant manifesting. Natives who are under the heavy thumb of Saturn might find it hard to connect to the Spirit of this Major Arcana.
Whereas, Pluto doms can learn not to fuck around with it too much (or too deep) the hard way, as they are known to manifest quite fast, but also quite fatalistically. So beware, do not try to force the connection, instead, give yourself space and time to 'test the waters' and see how well you fare with the cooperation of the Spirit of this card.
The Magician is teaching us how to wield and manipulate the elements, and he is giving us ideas on how to proceed further once we've managed to get down to the basics. However, when working with the Magician, it is of utmost importance to have a clear head and a direct vision of what you WANT to accomplish. Stay clear of your fears and things you dread in your heart of hearts, as it can prove to be perilous, and even lethal, when it comes to this card.
But it really is one of my favourite cards, and I always get joyous when I see it greet me with its bright colours in a reading. For me, it was always a messenger of good news and positive transformations.