What can I do to improve?

[Myrid 0]

So I know this is an extremely large question to look at for face value, but I am not happy with my performance on the Spriest and I want to find ways to get it up to par.
I've switched mains off from my rogue to the priest and just looking at A. the numbers I'm pulling and B. the %ranks I'm getting its a drastic difference. Looking at my rogue I have almost all ranks for my bracket above 95% but then coming over the the priest its all 40-70(ish)
https://www.warcraftlogs.com/rankings/character/19488063/latest/
what do you guys see that I'm doing super incorrectly? I'm sitting almost perfectly at the 12k haste soft cap and I can switch out my cloak to get a 4set but is it worth? I really feel like I'm missing a giant part of Spriest to really perform better, I mean just looking at logs of other people there is a drastic difference in damage.
so please help a nub like me out.

[Ramben 1]

Hi Myrid

I am by no means an expert at reading logs but here is my 2 cents:

 

For skorpyron:

Looks fine on this fight, only thing is that some of your void forms seems somewhat short (3 which ended at 23 stacks)

This fight is generally not a spriest friendly fight and the high parses are usually people somewhat cheesing the fight with heavy aoe setups such as SC and aoe trinkets. 
The job of a spriest on this fight is to do boss dmg. If no one are getting knocked out by shockwave, then just throw a dot or two on the big adds for ToF procs and otherwise just nuke the boss.

For Anomaly:

First spell should always be mind blast - did you VT+SW:P first?
You seem to be getting into voidform quick enough after it ends, keep it up (i assume the bigger gaps and lower voidform stacks from 01:30 - 03:19 is slow phase? If it is because of time bomb, the dmg is lower the farther you move from the raid group. Move like 15-20 yards from the circle thing on the ground and be in cast range of the boss and the dmg is very healable.
When did you pop hero? It seems like it was either in slow phase or did you screw up the voidform from 02:26 - 02:49?

Dont bother dotting the small adds on this fight. Dot the big one and burn it down with cooldowns. Try to snipe SW:D on the small adds. If you feel like it throw a SW:P on the small adds for ToF procs.

 

For Trilliax:

Same as before with opener
Use voit torrent on cooldown - only ever delay it if the boss is going to die within 1min OR you know that you would have to move within the next 4s
Voidforms with PI should be longer than 34stacks - aim for 38-40.
A few of your voidforms seems to be from 21stacks to 25stacks. Even without PI or hero they should be higher.
Try to aim for 15s between each voidform MAX, void form uptime should be around 70%, so you can get there
Try to time your 2. pot for when the boss hits 20%. This will mean ToF procs + SW:D + the pot - stacking CD's is always good.

 

For Spellblade:

Same as before with opener
Only 13 casts of SW:D when she spawns adds?
There seems to be some gaps between mind blast casts when she spawns adds - mind blast takes prio over getting dots up on the adds. If you have the 2set bonus start by dotting all of the adds first - its more micro intensive, but its more dmg done and more insanity duo to the bonus. But always mind blast > VT/SW:P
2 void forms of under 25stacks?
Same as before with void form uptime
 

For Tichondrius:

Opener
In your first void form there is a gap of 5s where you are not casting void bolt?
Tell your raid leader to pop hero when you get out of the first bat phase to push him down faster with the dmg buff. Make sure to snatch one when your in there btw
Not sure if you had enough insanity for a void form right after the bat phase, but make sure that you do. There is no blood adds yet so there is time for getting some boss dmg.
Seems like you used 2. pot at 20% - good
Keep working on your void forms, they are getting better - make sure to clip mind flay
Void form uptime is at 60.64%

For Augur:

Opener
I see that you used dispersion at 04:16: not sure if this was to counter fel nova or the like, but if you are ever to use it offensively then use it late in the void form to get more dot ticks off with more mass hysteria and void form stacks. I usually only dispersion offensively if it means i can cast void torrent.
There seems to be some gaps between mind blasts here and there.
- Make sure to use PW:S for speedup during frost phase to get to the edge faster and therefore can     start casting faster
- In the fell phase the dot from the fell corrupted ground (or whatever it is called) does not apply instantly after the zone is dropped so you can stutter step and cast while you have the debuff
Same for void form and their uptime

 

For Krosus;

Opener
Mind blast consistency - krosus will never cast fel beam (?) from the same arm twice in a row so move in advance. It will give you more time to nuke him without having to move
2. pot?
Good void form uptime
Amount of void form stacks is still low in some void forms - maybe you are moving to much?

For Botanist:

A few low stacked void forms
Some inconsistency in mind blast casts, my guess it is from the movement mechanics
Otherwise looking good

For Elisande:

2. pot?
Mind blast consistency - 10s gaps are to large even when the boss is moved to the new adds and you are hugging the wall - use PW:S to move faster if the targets are out of range
Try to get one more void torrent 
Your void forms are generally low on this fight
Not sure if im reading the log wrong, but did you not get the fast time buff at any point in the fight? If not you should get it - it is an insanely strong buff on spriests. Remember that you can not refresh it by simply going into the bubble when you have it already, but dip into the slow bubble and right back in to the fast bubble to get it refreshed

Thats my 2 cents for the logs
As for your question regarding the cloak it is hard to say since i was to lazy to look up your armory. 
But the tier items you should go for is Head, Shoulders, Chest and legs. I would rate the cloak higher than the gloves because of the gloves you can get from skorpyron.

Hope it was helpful 
GL

[Myrid 0]

My bad on a super later response, icy veins never notified me on a reply to the thread. When I posted this I was pretty low geared and frustrated that I wasn't doing better. Now sure how I can keep my void forms stacks higher without void torrent, even now with good gear ok struggling to get above 30 without void torrent but can easily get over 50 with it, so I'm obviously doing something wrong.

For Spellblade my dot casts are lowbecause I've had the legendary ring from day one, so dot spreading is easy.

Same with chrono, just putting dot on one little add and spreading to the rest.

Pure single target fights are where I'm really on the struggle bus even now, Krosus and star bro my ranks are not where I want them to he at all and I've been playing with STM to see but that hasn't seemed to help much. Love all your info and will take it to heart to improve.