Well, figured I'd steal this idea and make a thread of my own.
I feel like a video for a shadow priest would be REALLY boring, since it's mostly watching your timers and making sure everything is rolling on the boss.
First of all, I'll recommend some addons that I've found to be particularly useful.
DoTimer. (http://wow.curse.com/downloads/wow-addons/details/do-timer.aspx) Very handy addon that keeps track of your cooldowns and DoT spells.
MFClip. (http://wow.curse.com/downloads/wow-addons/details/mfclip.aspx) Another handy addon - this one will help you maximize DPS from your mindflay spell.
Decursive. (http://wow.curse.com/downloads/wow-addons/details/decursive.aspx) Nice for cleaning magic/disease debuffs in a raid.
Minor addons like OmniCC (http://wow.curse.com/downloads/wow-addons/details/omni-cc.aspx) are useful for watching your larger cooldowns like Mind Blast and Shadowfiend.
My armory. (http://www.wowarmory.com/character-sheet.xml?r=Zul%27jin&cn=Retso&gn=Horde+Defense+League)
Hit rating for a shadow priest is 289 if you take the Misery talent (which I would strongly suggest.)
I'll be talking mainly about boss fights, since trash usually either dies too fast or can just be AoE'd with Mind Sear.
Now then - first things first - in order to maximize your DPS from Shadow Word: Pain, you must WAIT to cast it. It is a good idea to stack Shadow Weaving from said talent first, as you will, ideally, only need to cast Pain once in a fight. This will also allow other beneficial debuffs to land on the target, further increasing the damage it does. It is also a good idea to get Replenishment rolling as soon as possible. Therefore, as a starting rotation, I do the following...
Vampiric Touch -> Devouring Plague -> Mind Blast -> Mind Flay (2 ticks, this is where practice with the MFClip addon is handy) -> Shadow Word: Pain
After your initial setup, there is not much of a set rotation. Mind Flay whenever Mind Blast is on cooldown, and all your DoTs are on the target. If a DoT is about to fall off, recast it ASAP. Don't be afraid to use your Shadowfiend - the cooldown is reasonable enough to use it 2-3 times in an Ulduar boss fight, and if all else fails, you can use Dispersion. I personally only use Dispersion whenever there is a lull in combat - whenever we have to stop casting during Ignis, whenever Razorscale does the Wing Buffet, running through the Safety Dance on Heigan, etc. (It is fairly easy to keep casting on Heigan during the safety dance, by the way. As long as you hit him with one tick of Mind Flay as you run through the dance, your Pain spell will keep rolling. Kills your DPS, but the damage is still there.)
Shadow Word: Death is an interesting spell. I mainly use it on trash pulls, near the end of the fight, just for kicks. However, it can be utilized pretty well on a fight that requires a lot of moving. If you've got to move, may as well shoot something at him.
Vampiric Embrace. What can I say. I tend not to use this unless the fight requires a lot of healing, or there is a steady health leech on the raid. Sapphiron is a prime example of this - it seems to help a lot. Be warned though, it can really skyrocket your threat, and with no way to stop the healing for 5 minutes, and no threat dump, you may find yourself threat capped.
Speaking of threat - Fade is nice, but (and this is mostly to non-priests) you have to understand how it works. Fade is not a threat wipe. Once a priest uses Fade, his threat appears to drop off the map, and, in a sense, it does. However, after the duration of the spell is over, you will pop right back up to whatever your current threat may be. If you watch Omen, your threat will stay constant, but will be in gray - Make sure your threat is not to high when the spell ends. You will most likely need to slow down your DPS in tandem with Fade - otherwise you may find the boss running your way in a few seconds.
Glyphs! The Major Glyphs I use are pretty much the standard. The Dispersion glyph is not very helpful, Mind Sear Glyph is nearly useless, and Shadow Word: Death Glyph is pretty situational. The minor Glyphs are pretty irrelevant, as the Shadow Fiend does not die very often, but it is nice not to have to carry/farm Light Feathers.
Here's a damage breakdown of a 10-man Emalon kill. (http://wowwebstats.com/fvlcudgj53ygy?s=625484-637845&a=x2000000010aff10) Mind Flay is your bread and butter, as you cast it the most. Note that even though Vampiric Touch had less ticks than either of the other DoTs, it still did the most damage.
That's all I can think of for now. Questions/comments are welcome.
Very nice write up...One other add-on I've used which helps with the timing on your rotation (not recasting too early and missing that last tick of VT, etc..) is Event Horizon:
http://www.wowinterface.com/downloads/info11935-EventHorizon.html (http://www.wowinterface.com/downloads/info11935-EventHorizon.html)
Unless I missed it, I wanted to add something regarding Shadow Word: Pain. When it is renewed with Mind Flay, it maintains whatever spell power it had the FIRST time you cast the spell. So, when you have something proc, like a trinket, the boosts your spell power, reapply Shadow Word: Pain. Mind Fly will maintain whatever bonus it had even after the proc timer runs out.
Oh, and another vote for Event Horizon, it's awesome.
Thank you so much for sharing all your knowledge. I just started a priest for my husband and I wanted to know is it better to have intellect over spirit of the other way around for a Pirest.
This post got really long, but I figure it'll be helpful for other would-be shadow priests. Sherri, to answer your question directly before I launch into more detail than you may have wanted, DPS wise, spirit is a bit more than twice as good as intellect. Read on at your own risk!
To really optimize Shadow Priest DPS, there are specific stat weights you want to keep in mind. All of the values are from www.Shadowpriest.com, which is a great resource. The following are the stat weights for a Shadow Priest at level 80 who is hitcapped:
Int = 0.22
Spi = 0.59
SP = 1.00 ( all values are normalized to SP, which is why it has the value of 1)
Crit = 0.76
Haste = 0.98
Your miliage will vary as you're leveling, but it's a good general guide. Remember though, this assumes you're hitcapped. If you're not, 1 point of hit is worth 1.88. So get hitcapped!
Here's an example of how you would use these stat weights:
Let's say you're trying to decide on a new helm. You are currently using HELMET1
HELMET1:
+50 Spellpower
+30 Intellect
+45 Spirit
+22 Stamina
+40 Crit Strike Rating
To calculate its rating, you multiply each bonus by the stat weight
Shadow Rating for HELMET1 = 50(1) + 30(.22) +45(.59)+ 40(.76) = 113.55
And you're considering HELMET2:
+30 Spellpower
+20 Intellect
+65 Spirit
+30 Stamina
+50 Haste Rating
Shadow Rating for HELMET2 = 30(1) + 20(.22) + 65(.59) + 50(.98) = 117.79
So HELMET2 would be a small upgrade over HELMET1. Notice that the Stamina value was not included, as this is purely a DPS calculation.
Recall that these examples assume you are (Level 80) hitcapped. Hit is better, pound for pound, than any other stat for DPS until you are capped. Not as big of a deal when you're leveling though.
But Joseph! (you might be thinking), I don't want to do a math problem every time I look at a new piece of gear! Right, me either, so you should get this handy Addon called PAWN. It will allow you to input stat weights so that everytime you mouse over an item, you get a rating for one of your values, like the Shadow Rating mentioned above. It doesn't work for Procs though.
Even better, when you get to level 80 raiding, shadowpriest.com has rankings for each slot done for you, along with gemming.
Hope this is helpful for someone at least.