(not aether, phrenology and phlogiston so much as i ching, tarot, bibliomancies and allegedly diagnostic panels and batteries of psychological tests . . . just kidding, those panels and tests probably go with the phlogiston).
my standard more-or-less-real-science comparison for the potential insight of astrology (specifically the birth chart) is the myers briggs personality type indicator, or kiersey temperament sorter, which you have likely encountered as part of some team-building program somewhere (total quality managers and their ilk believe learning about the MBTI encourages more personalized management, and fosters collegial sympathy), and which purports to classify personalities according to four descriptive axes into one of sixteen types. (there too, the serious literature reveals a dynamic rather than static system, but still: four axes, sixteen types).
um. the place to start is with a natal chart. this will be an image, most likely a circle with a cross through it and lots of symbols and probably lines everywhere.
the symbols identify two classes of arc of the circle -- domain of zodiacal sign, and house -- and the moving variables: the "planets" comprising those celestial bodies visible to the naked eye (uranus, neptune and pluto, some other planetoids, are often plotted and discussed, but for reasons of their extreme slow movement, their influence is better described generationally, socially or politically, than with reference to one person's life; also, the body of debunked and suppressed lore coalesced before there was awareness of these "trans-saturnine" planets).
this image describes the configuration of the skies at the moment and location of your birth (or the event being so contemplated). whether and how this has significance is up to you, though there are some services that will help, some.
the zodiac is universal (on earth: . . . terrestrial?): the circle is divided into the same twelve sections by sign for everybody, or on any chart for any event cast according to this convention -- there are other ways, but this one is dominant.
the houses are yours: the first and last (twelfth) houses meet at the point that represents the eastern horizon at the time/location of your birth, which should be the furthest left point of the image, and count counterclockwise. the size of each of the individual twelve houses depends on some calculations and considerations as to which i am insufficiently educated to opine; there are conventions and different options; i stick with the defaults (on automated astrological calculating services) until such a time as i'm sufficiently versed in the basics to venture into such nebulous realms.
that point where first and twelfth houses meet is the point of your "ascendant" - the degree of the sign of the zodiac that was rising over the horizon at the subject time/place; the signs run in order counterclockwise around the ring from that point. symbols of the planets are placed representing their respective positions in the sky so abstracted.
this is a natal chart. it is generated through relatively complicated (due mostly to consultation of ephemeris, constant time zone conversions, and calculations involving radians instead of rational numbers) mathematics that is all automated these days (if you can trust the programmers).
the art lies in interpretation.
the houses have relevant domains in your life: your home, your family, your vocation . . .
the signs have ambiance, influence and tone, more or less as they are popularly understood . . . with a lot of shading and nuance.
the planets have force and character: mars is martial; jove, jovial; saturn, saturnine, also more or less as popularly understood . . .
in a vacuum. all of these are sensitive to context and mutual influence. which is to say, perhaps jove isn't so jovial in a particular sign or house, or in a particular relation to another planet; perhaps saturn is oppressive in one sign and nurturing in another.
popularly, we describe ourselves by our sun signs. with access to a natal chart, we can take a little clearer snapshot, although it is still just a rough sketch, and look to the sun, moon and ascendant as indicative of something like superego, id and ego, respectively, or wholly-integrated person (obviously aspirational), emotional person, and personality, also respectively, or something not too unlike that. i, for example, have sun in aquarius, moon in leo and a scorpio ascendant.
it is the skill of weighing the various contending possible interpretations of the variables, their positions and influences, and crafting one uniting narrative that accounts for the necessity of each piece, or the skill of appearing to do the same, that i would look for in an astrologer. some of it can be automated, but not the nuance and interdependent influence... (yet?)
that is about what i know.
i recommend astro.com for free horoscopic calculations. should be able to join for free, and then navigate to the many free horoscope products (these are all marketing materials: anybody can have the abbreviated report for free in hopes that some will buy the real products, or subscribe to something; but they have some useful aspects). i recommend the "AstroClick Portrait" as the best learning tool. there, you can click on each element of your natal chat -- viz., from the signs themselves to particularly significant (in the estimation of the automation) angular relationship between planets or features -- and receive a relatively granular explanation of its significance, and links to related elements.
disclaimer: i have bought a product from this website, the basic psychological profile, some years ago. i just reread it, and am surprised . . . although i wasn't particularly critical this time.
(typically, reading such a document, one looks for the boilerplate language and the passages generated subject to variable/input -- like mad libs -- and tries not to be moved too much by those bits of the latter which would still appeal to any reader regardless of variables; i did not actively do that this time, although i did skip over entire sections already known to be dross).
but i don't think i learned anything new, either now or some years ago, except maybe a data point or two with respect to my interest in that lore's possible credibility. anyway, i told you that not to endorse the lore, but in case, should you come to consider buying such a product, you would care to evaluate a sample.
i have also found aleister crowley and dane rudyhar to be excellent authorities, though neither of them cares much, as writer, whether we can understand what he's writing about. crowley is hard to read at the best of times, but often a lot of fun . . . if arrogant obscure erudition is your thing (and if you already have the proper grounding in nineteenth-century comparative religion &/or closeted homosexual erotica to follow him. -ed.). rudyhar, an early twentieth-century theosophist of some sort, i think, writes very clearly and patiently, but on esoteric and technical points of astrology (much of his work freely accessible) that i can only learn from by accident, tangent, and maybe some kind of "trickle-down" osmotic cognition, though i'm doubtful. but, back when i put time into such researches, his was the clearest and most innately authoritative voice, and i felt like i was finally learning, or had finally found a source whose authority on the subject was apparent.
(y'know how i rhetorically asked "what does the one have to do with the other?," earlier, in reference a certain syndicated astrologer with short eyes, and more or less -- rhetorically, after all -- assuming the answer was something like "nothing, as far as we know?" remember that? you assumed "nothing, as far as we know" along with me because that's how rhetoric works. well, come to think of it, and in light of the foregoing paragraph's subjects -- crowley cultivated a reputation as quite the magickal operator, while we've all heard plenty about those theosophists' notorious parties and whatnot -- it may have been in error, or it may have been the ironic subconscious offering up another twisted dose of antihumor! seriously, though, i don't know anything about rudyhar as a person, and, while i know far more about crowley's many magickal operations than anyone should know of anyone else, i am nevertheless unclear on his accounts' literal veracity or any of the demographic particularities of any acolytes, amanuenses, homunculi, partners, scarlet women, macigkal co-operators, holy guardian angels or other persons who may have been involved. but there is food for thought beyond our earlier rhetorical supposition, eh? -ed.)
i have dabbled a bit in the tarot and i ching, also, learning a bit about the system, the process and the symbols. i do not have that talent: fitting all the pieces into a narrative that purports to describe a person or respond to a "querent's" question. also, i am too lazy to learn enough about astrology to develop that talent.
in the allegorical self-help book of life, i have gotten through all the prose exposition and am stalled out early in the exercises which fill the remainder of the book. anyway, i'm in it looking for insight and strange connections more than fortunetelling.
thanks for your interest and attention. now go forth and divine! pax vobiscum