There is the build I use for obvious reasons. Flash Fire for trash mobs and the single target damage still is not too bad. Dire Bats for the pure damage and ranged mob killing also a good spell when your kiting. Spirit Walk with Honored Guest to get out of sticky situations and regain some mana. Soul Harvest with Siphon... here's why i use this in particular: I can run into the mob somewhat as long as my Gargantuan is taking part of the damage and siphon 5 enemies with no problem and the damage they dealt while I was running into them is regained through Siphon. Spirit Barrage... my preference honestly not too big on the other spells minus Zombie Charger at later levels or even acid cloud isn't too bad but i find they take mana away from more useful spells like Dire Bats. Gargantuan literally speaks for itself, try it out and use it and you will see why its amazing, great damage and great tankability simply because everywhere you go your running into either an elite or at least a pack of 5 monsters. I bring Jungle Fortitude for more survivability, Spiritual Attunement for more mana and obviously more mana equals more DPS. Spirit Vessel is simply a life saver but can be replaced with whatever you prefer.
There's my take on the skills that I use and I've made it all the way to Hell solo'ing.
Gear: I go to the auction house and set the level parameters and go for intellect and vitality on all my gear... the third stat varies by the piece of gear that I am searching for! I prefer Life Steal on my weapon as the third stat and usually look for a socket too. The rest of the 3rd slots are preference.
My Solo Boss build looks like this :
I just switch for splinters for the single target DPS. Bad Medicine works hand in hand with your poison damage obviously. Haunt with Resentful Spirit is a great single target DoT skill... enough said.
For all trash mobs I just kite as much as possible and utilize hit and run.
As for a follower I use the Templar and keep his gear as up to date as mine.
Everyone knows each character has an attack animation and at lower levels none of us have the attack speed to just stand there and be able to attack without any animation. So if you time it right you can shoot, run long enough for the animation to reset then shoot again. When you become good at this you can wreck just about any mob in the game even the pesky mortar mobs.
If anyone has any questions on gear or just Witch Doctors in general I will answer them as best I can because I've spent the entire time leveling trying out different builds and things and there are other builds that work, I just find this one best fits my play style!
Good luck and remember to have fun and play the way that suits you best and you will go alot farther than people following the trends.