First of all, you want to farm and gamble for the Shield (stats don't matter on it for now, ofc it's nice to have 10% Crit on it but take whatever rolled Unrelenting Phalanx you can get for now), I recommend running a different Specc till you optain the Shield, for example Shotgun or just a simple Hammer build. Use a Fury Generator instead of Judgment till you finish your Akkhan Set wich is the next checkpoint to get, don't forget to farm a Ring of Royal Grandeur too. After that, focus on Wrists till you get Strongarm Bracers, these are definatly essential in this build. While farming these items, you should have been able to equip yourself with full Legendaries in the other slots wich you found while farming. Next up, you want a Leoric's Crown, wich obviously is a huge upgrade too. Now at the latest you should also make sure that all your gear has propper stats, especially Physical Damage on your Bracers, Sockets in your Rings/Amulet, 90+% Crit Damage on your Amulet and get a Unrelenting Phalanx with "acceptable" stats (meaning at least having the Crit on it) wich all are the most important Damage Boosters stat wise. Now you can start to gamble on your Weapon and try to get a Hearth Slaughter wich is pretty common, don't aim for Furnace since it's just too rare to gamble for it at this stage, be happy with your Heart Slaughter and big congrats if "accidently" a good Furnace pops up Now you want a good belt, wich you probably already got, especially Vigilante Belt drops a lot. Last but not least, you want to have 2 Unitys when going Solo for you and your follower, when going in a Party, skip Gambling rings for now since SoJ is just too rare. More importantly, you now want to min/max your gear a bit, at least to an acceptable degree, meaning you have the highest priority stats on all your pieces, they don't have to be max rolled yet. Now you can gamble for all the fancy stuff like Furnace, SoJ, Witching hour, a really well rolled Amulet and so on. After that, you simply try to max out the stats on your gear till your Crusader reaches perfection!

Summary: Unrelenting Phalanx > Akkhan Set + Ring of Royal Grandeur > Strongarm Bracers > Leorics Crown > "ok" Stats on your gear overall > Strong Weapon (Idealy Heart Slaughter for now) > Vigilante Belt > 2x Unity (when Solo, otherwise skip this step) > Min/Max a bit to get Stat priorities correctly > Super good rolled Amulet > Furnace / SoJ / Witching hour and other rare stuff > Min/Max your rolls to reach perfection