As a resource, mana hasn't changed much since Diablo 2 compared to other classes. Mana is the slowest regenerating resource by the time you reach the endgame, but it also manages to raise in how much you can reserve as you level. To follow this, most of the Witch Doctor's skills will also increase in cost, and with the omission of mana pots this time around, different tactics have to be taken this time around to make sure your blue globe isn't dry. One such solution is by focusing in the spirit school:
Active Skills
-The Spirit is Willing
A pretty no-nonsense nuke here, Spirit Barrage does great damage for a very cheap cost. A Golden Runestone here adds some mana return after your done bombarding the target.
-Draining Spirit
Extremely potent damage over time spell thats pretty easy to keep going considering it will find a new target after it's first is dead. Better yet, with another Golden rune, this spell will be better than free, coming out with a net gain of 300% mana cost after the dot has run it's entire duration. Great with packs of enemies, no need to spam on bosses and uniques though.
-Vengeful Spirit
This one on it's own is a great self buff that will help empower your main damage spells. Alabaster sweetens the deal by making the 5 afflicted enemies take 250% weapon damage, meaning you can get in with some of your enhanced physical damage if you feel like or let your party start wailing on your foes like crazy.
-Ruthless Terror
Fantastic defensive cooldown that can really get you out a tight jam. If your feeling low on mana, you can set this up for some major returns from your Gold by getting into a pack and send them scuttling in fear. Bonus points for Soul Harvesting first.
-Healing Journey
Another great defensive cooldown that will let you get in/out of a large group of enemies. An Alabaster here will restore almost half your life if you can let it run it's full duration. The cooldown period is only 15 seconds, so make use of the healing whenever you can.
-Paranoia
Mass Confusion on it's own can be a real game changer, cutting your foe's forces in half and giving you some buddies for a little while. Add in the 80% increased damage buff and you can absolutely decimate a large group of foes. This will also work great for Bosses and Uniques, if only for the extra damage
Passive Skills
-Rush of Essence
The passive that makes a spirit doctor, by spacing out and rotating your skills around, you'll be passively regenerating twice the amount spent on each spell over the course of 10 seconds. Granted some of the skills (even ones listed on the passive) don't actually have a mana cost, but between the ones that do and the Golden Runestones socketed into half your skills, you should be swimming in mana...
-Pierce the Veil
...maybe even too much mana, but thats where Pierce comes in. 20% damage for 30% cost is a real bargain considering most of your skills will be giving you a net gain of mana anyway. Pretty much gravy for this build
-Vision Quest
The last bit for mana management. With the Runes set up in this particular fashion, your looking at 2 15-second cooldowns, a 20-second cooldown, and a 60-second cooldown. Opening up with Mass Confusion, followed by as many of your other long cooldowns as possible will put extra damage on the board, top off your health, fear a lot of foes, and then start up the 300% regeneration phase. Once you've got this going, feel free to start haunting and barraging as much as you can before Harvest or Walk come off cooldown.
Lots of room for tweaking here, as some of the mana return may be overkill or underwhelming depending on your playstyle. Add more Golden Runestones if you find yourself going dry, otherwise swap some out for more interesting abilities. If you end up dropping skills with long cooldowns, it will be to your benefit to swap out Vision Quest for something else, such as Spiritual Attunement. Another possibility is throwing in a skill to drain excess mana, such as Firebats or Wall of Zombies (great with fear).
