There is a plethora of information on the internet regarding tango etiquette - and for good reason.
Tango is an intimate dance so a set of "codes" that are understood and respected by all are of great importance. Instead of rewriting what has been so well written already, I refer to you a few pages and links below.
TANGO MANNERS by Tine Herreman
AN EXTENSIVE RESOURCE ON ARGENTINE TANGO from TejasTango
The history of tango music is as rich and interesting as the dance. Tango music in Argentina followed much the same evolution as swing music did in the United States. It started as simple rhythms played for dancers by orchestras led by some colorful and charismatic bandleaders. Over time, simpler rhythms evolved to more complicated ones and finally edged toward more jazz-like interpretations less suitable for dancing but wonderful for listening.
Tango music is probably most distinguished from other types of music by two things: the bandoneon and the lack of drums. The bandoneon is a German instrument that looks and sounds like the offspring of an accordion and an organ. In fact, the instrument was invented to provide organ-like music to church congregations unable to afford a real organ. Like a lot of immigrants to Argentina, the bandoneon found its way into the culture and left an indelible mark on it.
You may also notice that there are no drums in tango music. The beat is kept on a bass and the lower register of the piano with (usually) bandoneons, violins and the upper register of the piano providing the fascinating rhythms.
When you start dancing tango, you'll most likely be dancing to the most rhythmic music from the 1940s and 1950s known as the Golden Age of tango. Music from the late 1930s is also great for learning how to hear the beat and feel the rhythm. As you become more experienced, later music (including that of modern tango orchestras) with its more modern jazzy rhythms becomes very interesting to interpret.
To develop your understanding of the music, you may want to consult the guide Music for Dancers New to Argentine Tango. It lists the CDs best-suited for dancers first learning to hear the rhythm of Argentine tango music. - Tejas Tango
Argentine Tango Music links to get you started:
TANGO MUSIC SAMPLER LIST - 60 Songs (Download Song by Song) by J. Abling
Tango Music Sampler (Download Compressed Folder of 60 Songs) by J. Abling
ARGENTINE TANGO MUSIC by DJ Tine Herreman
TANGO ARGENTINO DE TEJAS Guides to Tango Music for Social Dancing by Stephen & Susan Brown
THE POETRY OF TANGO
TANGO ARGENTINO DE TEJAS
GO TANGO WORLDWIDE
TODO TANGO | lots of links, incl health benefits of tango
HISTORY OF TANGO
TANGO VOICE BLOG
TANGO THERAPIST BLOG
MAPDANCE.com | an app listing dance events, festivals and studios worldwide
MELINA'S TWO CENTS BLOG
MONICA PAZ PRACTIMILONGUERO | Milonguero Interviews, History from Teacher Monica Paz's site.
CACHO DANTE MILONGUERO | https://cachodante.wordpress.com/
LA MINA TANGO | Tango shoes and Clothing from BsAs
JULIE BELLA | DC's own dealer. Comme il Faut shoes & clothing
GUARANTEED FIT SHOES | Great selection & Guaranteed fit for men and women
2x4 AL PIE | High Quality Men's Tango shoes
ARIKA NERGUIZ | Online designer shoe store
FELINA SHOES | NYC dealer of Comme il Faut & NeoTango
MALEVA SHOES | Comme il Faut & Maleva
MADAME PIVOT | Italian Tango shoes