Note that the following is generally based on the experiences of this ladder. From what I heard, the Dreamlands may be more difficult next time, so keep that in mind.

1) Pick a build whose set gear is fairly easy to find or obtain through trade (IMO, The Barbarian and Paladin's gear are the hardest to find though both are quite worthwhile).

2) Farm cows and plaguelands for any charms you may need along with rare rings or amulets you think will be sufficient for the time being (you should also be taking this time to collect organs, runes, perfect gems, and jewels and maybe certain rare items to complete your whole setup for the time being).

3) Get uber keys

4) Get fragments and do Worldstone (try to call a GM or friend here for help and also to prove you opened the Worldstone in case a crash occurs). Note, consider buying Belial's Tome beforehand if Mana is a problem for your build. This isn't necessary, but it could be quite convenient depending on your build.

5) Get (or buy depending on your build and gear) Alkor's

6) Depending on your build, gear, and changes in the next ladder, try to farm the Act 5 pits, Inferno Cows, Lich King, and dreamlands for any item you need (or are willing to trade).

7) Farm the time rift for anything you need there (or are willing to trade)

8) Farm for anything else you will need before doing Crucible and consider either joining a clan or making one to do this.

9) Farm Crucible.