Caprica.

Blood & Chrome.

BSG: The Mini-Series.

BSG: Seasons 1-2.

BSG: Razor takes place between Season 2, Episodes 17 and 18.

BSG: The Plan takes place betwen the mini-series and Season 2, Episode 20.

BSG: The Resistance webisodes.

BSG: Seasons 3-4 (Part 1)

 

Because someone wants to know how to watch Battlestar Galatica in the chronological order.

 

Many thanks to the Wertzone:

 

http://thewertzone.blogspot.com/2016/04/battlestar-galactica-viewing-guide.html