Diablo III- Skills Article CLXXXIX: Witch Doctor Elective Mode Build Three- Mana Pool

Mouse Skills:
Corpse Spiders (Widowmakers)
Firebats (Hungry Bats)
Hotbar Skills:
Acid Cloud (Acid Rain)
Haunt (Draining Spiirt)
Soul Harvest (Swallow Your Soul)
Big Bad Voodoo (Rain Dance)
Passive Skills:
Rush of Essence
Spiritual Attunement
Vision Quest

The main sources of Mana expenditure here are Acid Cloud and the Firebats.  Both these skills consume remarkably large amounts of Mana and lack cooldowns, making them excellent ways to dump a lot of resource very quickly for very high damage.  Acid Rain is chosen for area of effect, and Hungry Bats for the combination of high damage and not needing to actually aim very much.  The entire rest of the build is geared towards funding the use of these two high-cost skills.

Corpse Spiders is present at last, and in the Widowmakers form- since it’s the lowest-cost skill available to the Witch Doctor (outside of Toad Affinity Plague of Toads and the no-cost cooldown skills), and the spiders grant you Mana every time they hit anything, it’s a good way to steadily generate Mana, even after you turn your attention to your other skills.  Vision Quest enhances this further by improving your Mana regeneration after you throw a spider jar.  Rain Dance lets you pull up even more Mana by standing in it, especially since you can then throw Spiders even faster.  The Haunt will deal out additional damage and give you even more Mana restoration over time, and Soul Harvest’s effect on Intelligence not only increases your Mana pool, it also boosts your damage and Mana recovery.  This is especially nice with Swallow Your Soul, which makes the skill more than refund you for its cost as long as you tag at least two things with it.

Rush of Essence causes both Haunt and Soul Harvest to refund you even more Mana over time after they are used.  Vision Quest does something similar to Corpse Spiders or any other of the four lowest-cost no-cooldown Skills you choose to use if you find Widowmakers isn’t working for you.  And Spiritual Attunement both improves your Mana pool’s size and boosts your Mana recovery regardless of what you’re doing.

This skillset works fairly well against Bosses despite being essentially specialized to kill large numbers of enemies via constant Firebats and Acid Clouds.