Sith's Umbramancer Guide
The Actively Inactive Class
Umbramancer at first glance seems like a class where you'll need to constantly have Idle Wizard in front of your face clicking that orb, but as it turns out, it's quite the opposite. It seems confusing at first, but hopefully a run or two with this guide will help clear it up for you. 
Seethe In Shadows
Attributes
It may come as a surprise, but [Dominance] is the main stat for Spooky boi here, followed by 125[Spellcraft]/75[Mastery]. The reason for this is Umbra's main burst spell, Seethe In Shadows, is boosted by autoclick power, and Umbra's main build up spell, 
Eclipse, is an accumulated that takes some time to build to a worthwhile amount so the 125 [Spellcraft] node helps speed that up.
[Intelligence]/[Insight] are the dump attributes. [Intelligence] will give you the flat source/myst boost, but [Insight] is only useful for 
Shadows Of The Void because [Insight] does NOT increase the amount of Liquid Shadow(LS) you receive from Shadow Clots (Entities).
Ex.
At 300: 150 [Dominance], 75 [Spellcraft], 75 [Mastery].
At 450: 150 [Dominance], 125 [Spellcraft]. 75 [Mastery], Rest for gear (100 [Intelligence]).
At 650: 150 [Dominance], 150 [Mastery], 125 [Spellcraft], 150 [Intelligence], 75 [Insight]
If you are below 300 attributes, you can still use Umbra. As long as you have the [Dominance] you'll make progress, but I'm sure you get the idea of the attribute spread.
Start of Run
You will want to stay as Apprentice and level as much as you can using 
Conjure Manabeast, 
Conjure Primal Elemental, 
Void Lure, and whatever else you desire while leveling Spellhound/ Arcanaworg. After you levels slow down (ideally where you can use all of Umbramancer's spells, but the further the better), you can switch to Umbramancer and begin the Stacking Phase.
If you don't mind extending your run you can use Homunculus/Simulacrum, but the only important source is Mana Gems (Shadow Coals).
Stacking Phase
This is where the majority of the time spent in the run will be, roughly 60% of it.
Right after you switch to Umbramancer, You'll want to put Eclipse on the spellbar and set it to reckless. The goal is to constantly run out of LS. When your LS is empty the spell will cancel, but since it generates over time the spell will recast. Feel free to add Conjure Manabeast, Conjure Primal Elemental and whatever else you'd like. The important part here is Eclipse stacking so don't use anything that helps gain LS.
P.S.- The "Drain" of LS that Eclipse and 
Onyx Hound have does NOT count towards Umbramancer's "Liquid Shadow Spent" passive.
P.S.S.- After you click the orb enough for XP and the Shard Pool Upgrades (200 manual clicks) then you can stop.
Build Phase
This should be until _e6/_e7+ Liquid Shadow, depending on your mysteries. This should roughly take up at least 30% of the run.
The spellbar for building should be 
Condensing Shadows, Onyx Hound, Conjure Manabeast, 
Dancing Flame, and 
Day Into Night. The last spell slot is for filling up your other spells and for Conjure Primal Elemental when they're all ready. Sit in idle mode as this will take a while without the Umbramancer pieces (Neck and two rings).
The Spells to charge are:
P.S.- Stay with worg for this.
Burst Phase
This is the only active part due to needing to click the orb occasionally to reset the Umbral Rage cost and switch the spells out.
Still with worg, swap out Onyx Hound, Conjure Manabeast, Conjure Primal Elemental, and replace them with 
Critical Mass, Shadows Of The Void, and 
Umbral Rage. Only cast Umbral Rage while manually casting Day Into Night to keep it going. Be sure to click the orb occasionally to reduce the cost effect of Umbral Rage. The hardest part of Umbramancer is keeping Umbral Rage going.
After you've gotten this process going, switch out Day Into Night for Seethe In Shadows and switch from Arcanaworg to Shadow Stalker/Ebonsand Behemoth. As Ebonsand Behemoth levels slow down, replace Condensing Shadows and Dancing Flame with Eclipse and 
Empower.
Once you're down to about 2e5 Liquid Shadow (Or roughly 20% of your total), It's time to burst. Manually cast everything, but put Seethe In Shadows on reckless. Be sure to quickly buy upgrades, sources (Shadow Coal priority), and click the orb to reset your costs and keep your burst going as long as possible.
If you don't feel like you've made enough profits in the first cycle, just start over at the LS Build phase. The LS you spent will make up for not building Eclipse more, but you can if you'd like. Since it isn't a persistent I wouldn't recommend spending too much time on it.
P.S.- If you wish to go through your LS slower, feel free to replace Seethe In Shadows for 
Flash Fire while switching to Ebonsand Behemoth, but be sure to use Seethe In Shadows for your actual burst.
Notes
Thank you for checking out my 2nd guide! Hopefully this helps clear up the confusion that is Umbramancer. This guide should be useful at any mysts with the only difference being the duration of the runs and the amount of LS to work with. Gear is a completely different animal that I haven't tested yet, but I'd go with Evocation/Incantation gear -or- Autoclick profit/Evo/Inca gear depending on what you have unlocked/upgraded.
For another confusing class, check out my Chronomancer Guide!