Users frequently ask me where they should begin when first jumping into the EU. Because I simply have no interest typing out extensive descriptions to answer that question every time, this is where those questions will now be directed.  
 
There is an immense amount of reading material with well-defined but less than obvious placement in continuity. Comics and books all have a set date, as the EU is extremely concerned with establishing time frames. There is a date system that has been developed to express the exact point at which a given story arc took place or character lived or item was discovered. The system is BBY (Before Battle of Yavin), also known as BSW4 (Before Star Wars Episode IV), and ABY (After Battle of Yavin), also known as ASW4 (After Star Wars Episode 4). Different works have been written from dates ranging from roughly 5,000 BSW4 to over 130 ASW4. While there is information provided in sourcebooks pertaining to histories long before 5,000 BSW4, there are no comics or novels written before that time.  
 
With the date system shown, the eras are what separate these less specifically. There are six eras: Old Republic era, Rise of the Empire era, Rebellion era, New Republic era, New Jedi Order era, and Legacy era. I may refer to these by an abbreviated term, particularly OR, RotE, R, NR, NJO, and L respectively. The Old Republic era began at approximately 25,000 BSW4 and ended at roughly 1,000 BSW4. The Rise of the Empire era ran from 1,000 BSW4 to 0 BSW4. The Rebellion era ran from 0 ASW4 to 5 ASW4. The New Republic era spans from 5 ASW4 to 25 ASW4. The New Jedi Order era covers 25 ASW4 to 40 ASW4. The Legacy era extends from 40 ASW4 and beyond, the latest time existing in any story line being 138 ASW4. Now, the end of the RotE era is the time period in which Emperor Palatine and Darth Vader rose to power. The Rebellion era is the time when the Rebel Alliance engaged the Empire in the Galactic Civil War. The NR era is the years following, when the Alliance founded a New Republic in the aftermath of the Sith's defeat. The NJO era shows the reforming of the Jedi Order after the Jedi's destruction from the Great Jedi Purge. And the Legacy era continues to portray the New Jedi Order and occurrences long into its future. Addendum: To be perfectly accurate, there is another era before the Old Republic era, which is called the Pre-Republic era. But this era will not be featured in this blog because there is virtually no material in this era and mostly only described in sourcebooks
 
I listed all of that because to begin reading in the EU, you have to select an era that interests you. You could of course just read from multiple eras simultaneously, but there are a few stipulations: The NJO and L era are not to be read unless NR era comics and novels have been read first. Otherwise, you will be lost in what is happening, because stories are interrelated and consequential to one another. The OR era is more or less free game. Anything can be read from this and in some cases without prior reading. In the RotE era, this is also true but to a lesser extent. With the Rebellion era, if you have watched the movies, you do not have to read anything out of this time, although doing so is still good, because there are significant events in this period. If SW books/comics centered on Luke, Han, and Leia interest you, then read into the Rebellion era or dive into the NR era. In the NR era, there are numerous important story arcs that need to be followed in order to read NJO and L era works with the same characters. However, in the Legacy era, the Legacy comic series can be read without very much study of events beforehand, because it happens over 100 years ABY.  
 
For each era, I will list what is most important. 
 
OR era: For this era, the Tales of the Jedi comic series is essential. This series has drastic impacts on continuity and is just a great read as a whole. Like most Star Wars comic series, TotJ is divided into story arcs, each consisting of 5 to 6 issues (usually). The first arc is simply Tales of the Jedi (or Tales of the Jedi: Knights of the Old Republic). The next is TotJ: The Freedon Nadd Uprising. After that, TotJ: Dark Lords of the Sith, then TotJ: The Sith War, then TotJ: Redemption. These catalog the exploits of Ulic Qel-Droma and Nomi Sunrider as two of the main protagonists and is situated at 4,000 BSW4. After reading these, read the prequel series, Tales of the Jedi: The Golden Age of the Sith and Tales of the Jedi: The Fall of the Sith Empire, which happen around 5,000 BSW4. Other notable EU stories at this time are the Knights of the Old Republic video game series and comic series. KOTOR and KOTOR II: The Sith Lords are excellent RPG-style games, and the KOTOR comic series grants some details on them as well. 
 
RotE era: For the beginning of this era, the Darth Bane novel trilogy is basically all there is but necessary. The Bane novels show how Bane founded the Sith Order that resulted in the fall of the Republic. Darth Bane: Path of Destruction, Darth Bane: Rule of Two, and Darth Bane: Dynasty of Evil. In the latter portion of this era, the Republic comic series extrapolates what was before the prequel trilogy to a degree and events between them. It was not compiled into Republic until midway through the series though. They were simply individual story arcs with no name in common with one another aside from simply Star Wars. The first story arc is, technically, Jedi Council: Acts of War and then Prelude to Rebellion (full lists of all of the story arcs can be found on the SW wikia, if I am not mistaken). Other worthwhile reads include the prequel to the Phantom Menace, Cloak of Deception, the Clone Wars novel series (Shatterpoint, The Cestus Deception, The Hive, MedStar I: Battle Surgeons, MedStar II: Jedi Healer, Jedi Trial, Yoda: Dark Rendezvous, and Labyrinth of Evil), Outbound Flight, Dark Lord: The Rise of Darth Vader, and others. The prequel novelizations should also be read. 
 
R era: As a general rule of thumb, the novelizations of the movies should be read. They can be bought in collections of each trilogy and are overall just more rewarding than the movies and grant intriguing information. Some Rebellion era works to be read include Splinter of the Mind's Eye (takes place between A New Hope and The Empire Strikes Back), Shadows of the Empire (takes place between The Empire Strikes Back and Return of the Jedi), and Truce at Bakura (takes place the day after RotJ and into the week following). There are other novels in this period as well such as Death Star and Allegiance.  
 
NR era: The earliest possible work for this era is Luke Skywalker and the Shadows of Mindor. This is a great book but was written in the last decade and thus was more filler than anything else. It is not essential reading but still worth reading. Books to start with in this era would be either The Courtship of Princess Leia or X-Wing: Rogue Squadron. The X-Wing series depicts much of how the New Republic was built after the Galactic Civil War. Whether the X-Wing series is read or not, Courtship is needed. After those, the Thrawn trilogy is the year after, next on the chronology, and absolutely mandatory. Heir to the Empire, Dark Force Rising, and The Last Command have to be read to continue in this era. These books were adapted into comic versions, which could be read in substitute for the novels if need be. I will not be listing any more on this era because this should be enough of a start. 
 
No listings will be given for the NJO or Legacy eras here because you should not be reading those unless you have read all major New Republic era story arcs. (If you need help with those, you can still ask here, but this blog is about where to start reading. Those eras are for seasoned followers of the EU.) 
 
Hope this helps.