Just study, Read Articles on forums and Watching Minecraft Videos of Famous youtubers like PrestonPlayz and some GC youtubers such as JeffyBoyy
First of all, this thread is to tell what you do while NOT playing gc... second, I dont bully you (facepalm)
You said what u do when GC is down... I ran on another server to make a build for 4 hours Otherwise play Lan or go through forums(like right now)