In order to access this authority, we must first get to the point where we reclaim our Race and Value, as Plotinus put it. There are various means to accomplish this. My personal favorite is being Born Again in the Spirit, but I'm a ecstatic Christian, so what can you expect? The major downfall of this method is that the best environment for receiving this rebirth, or "baptism of the Holy Spirit" is in a fundamentalist charismatic Christian Church, and while the spirit of God is awesome, the people in the churches... well, they aren't exactly... centered. Usually.
Within the Western Mystery Tradition (WMT), other means exist. Knowledge and Conversation with your Holy Guardian Angel (K&CHGA) is one way. I personally believe this is a necessary first step in every magician's practice. Once this has been accomplished, you're guaranteed access to the Governing Spirits of the Planets, and you can begin to work with them to harmonize your sphere with theirs, thus eliminating the stumbling blocks in the areas of your life that are governed by their assigned rays. Integrating the powers of the planetary spheres into your own sphere results in progress along the Great Work, the elimination of character flaws that hinder your satiety, and wisdom in the realm governed by that particular sphere.
For example, if you're chronically unlucky in business, this could indicate that you're out of tune with the sphere of Mercury. In such a circumstance, you would conjure the Governor of Mercury, and ask it to integrate the powers of Mercury into your sphere. Soon after the ritual, you'll find that patterns of inappropriate behavior become apparent in your life. When you've identified these patterns, you work with your HGA to change these patterns of behavior, isolate the root cause, and reclaim that part of your life, putting it in its proper place. Eventually, you'll find that you're not ruled by misfortune in areas of business, instead you're dictating through Mercury how your success in business will manifest in your sphere.
This can be applied to the other planets as well. Agrippa gives the following attributes to the planets in chapter xxxviii of Book 3:
By the seven Planets as it were by instruments, all powers are diffused into man from the Supreme fountain of good: by Saturn a sublime contemplation & profound understanding, solidity of judgement, firm speculation, stability and an immovable resolution: by Jupiter, an unshaken prudence, temperance, benignity, piety, modesty, Justice, Faith, Grace, Religion, equity, clemency, royalty; by Mars, truth; not to be terrified, constant courage and fortitude, a fervent desire of animosity, the power of acting and the practice, and an in-convertible vehemency of the mind. By the Sun, nobility of mind, perspicuity of imagination, the nature of knowledge and opinion, maturity, counsel, zeal, light of justice, reason and judgement distinguishing right from wrong, purging light from the darkness of ignorance, the glory of truth found out, and charity the Queen of all virtues: by Venus, a fervent love, most sweet hope, the motion of desire, order, concupiscence, beauty, sweetness, desire of increasing and propagation of it self; by Mercury a piercing faith and belief, clear reasoning, the vigour of interpreting and pronouncing, gravity of speech, acuteness of wit, discourse of reason, and the swift motions of the senses: by the Moon a peace making consonance, fecundity, the power of generation and of growing greater, of increasing and decreasing, and a moderate temperance, and faith which being conversant in manifest and occult things yields direction to all; also motion to the tilling of the earth for the manner of life and giving growth to it-self and others.
The Spirits of the Planets have their own hierarchy. Different Grimoires provide different interpretations, but for the sake of simplicity, each planet can be said to have an Intelligence that acts as a mediator between the lower realms and the higher realms, and a Spirit that acts as a mediator between the higher realms and the lower realms. The magician (generally speaking) works with the Intelligences on matters of spiritual growth, and the Spirits in matters of material manifestation. The Spirits, while extremely powerful, are placed under the authority of the Intelligences.
For Work that results in material gain, like fabulous riches, you might start by working with Your HGA to identify the best means to get the fabulous riches to manifest in your life, and identify the appropriate planet to work with. This could be Jupiter, if you want to get rich by gaining promotions and responsibilities in your career, or the Sun, if you want to discover fabulous riches that were previously hidden, or Mercury, if you want to get rich through quick-witted transactions. Your HGA will guide you to the appropriate planet.
Once you've identified the appropriate sphere, you'll want to ascend to the Intelligence of the sphere and enlist its aid in preparing you to receive the manifestation, and in getting its help in directing the Spirit to manifest the riches in the best possible way in the material realm. Then you would conjure the Spirit of the planet, and give it detailed instructions. the Spirits of the planets are incredibly powerful, but not necessarily intuitive. They'll often do what you say, not what you want. That's why it's important to work with the higher spirits first.
Now, if you're in a hurry, you can also choose to work directly with the lower spirits, those closer to the material realm. Each of the spirits and angels in the various Grimoires are usually listed with some reference to their planetary governor, and you would work these spirits through the authority of their higher-ups.
In the next section, I'll get into Talismen, the most effective means I've found to direct the rays of the planets into your personal sphere.