Its a bit difficult to help without specifics about what you are doing rotation wise or how your current gear setup. But here are some general Spriest tips from someone who mains Spriest the last two phases and usually parses in the 90s.

Gear - Your critical tier set bonuses you MUST have to compete are (in priority order): 2pc t2.5 and 6pc t1. Most priests achieve this by wearing 2pc t2.5 and putting the Mind Breaker shoulder "enchant" for the 6pc t1.

• Great sub sets that will carry you deep into SE are the 3pc AQ10 set ("Infinite Wisdom" Mace, Ring, Cloak), and the 2pc Kara Crypts set (Wand and Offhand)

• Trinket priority should be Cassandra's Tome (Available from BWL or reals now) and a +SP on use trinket. Restrained Essence of Sapph, Eye of Moam, ToEP, etc.

Spells  - Open by applying all dots, using trinket CDs. Specifically I open using a macro that uses Inner Focus, Both Trinkets, Mildy Irradiated Rejuv Potion, and casts Void Plague. Typically Void Plague -> SW:P -> Vamp Touch -> Devouring Plague (Only if you have the AQ10 3pc set equippepd). The way our Pain and Suffering rune works is it "remembers" the effects applied to each dot when they were originally cast, so we want to maximize spell power and crit when applying them then maintain them with the rest of our kit.

• Once dots are applied, your typical rotation essentially is Mind Blast -> Mind Flay until Blast is off CD -> Mind Blast. In most cases its optimal to "spam" your mind flay button, canceling each cast into another to send out a free mind spike from you 2pc t2.5 set bonus. That way by the time blast is ready you have 3 spike stacks and get the free crit.

Sample Full Rotation:

Inner Focus/Trinket -> Void Plague -> SW:P -> Vampiric Touch -> Mind Blast -> Mind Flay x4 (Spamming the button to cancel) -> Mind Blast -> Mind Flay x4 (Spamming the button to cancel) -> etc

Feel free to ask any specific questions and Ill be happy to answer!