After learning the basics about each of the zodiac signs, planets, houses, and aspects, it's very easy to hit a learning plateau in astrology.
Here's some of the books which I think can really deepen and expand your knowledge:
The Twelve Houses - Howard Sasportas
The Twelve Astrological Houses - Dane Rudhyar
Aspects in Astrology - Sue Tompkins
Anything by Liz Greene!
Astrology, Psychology, and the Four Elements - Stephen Arroyo
Symbolism, Mythology, Archetypes
Jungian Symbolism in Astrology - Alice O'Howell
Making the Gods work for you - Caroline W. Casey
Archetypes of Astrology - Ena Stanley
On specific planets
Healing Pluto Problems - Donna Cunningham
Predictive Astrology:The Eagle and the Lark - Bernadette Brady
Cosmos and Psyche - Richard Tarnas
The Rulership Book - Rex E. Bills
And here's some more free resources you can use:
- Chris Brennan is an astrologer with two amazing projects, namely The Astrology Podcast (I particularly recommend the episode Tips for Becoming a Better Astrologer in this context) and The Astrology Dictionary
- On Elsa Panizzon’s website, you can find a Transit Calendar
- You can use astrotheme’s data base to look up celebrities with certain natal chart placements
- My favorite (non-tumblr) astrology blogs include The Astrology Place, Sagittarian Mind, AstroFix, and Astrology Arena.
- There’s tons of free astrology articles on SkyScript.
If you have any recommendations yourself, please share them in the comment section :)