I recently finished leveling my warlock and have began to raid in Normal HFC and some Heroic HFC. And I've spent a considerable about of time trying to figure out why im only pulling in the 25kdps-38kdps on various bosses in HFC. While i see other Warlocks of my ilvl (701-703) pull upwards of 40-50k easily during almost every fight. 
 I know its not optimal a single log output but its all i had on hand and i'm just super frustrated and looking for some advice. (from Korm on normal HFC)
I follow the Icy-veins destro guide for single target rotation.
That being,
1 Immolate on at all times refresh about 3 seconds
2 Conflagration if i have 2 charges. (been trying just using both charges at once not seen a big difference)
then incinerate until 2.5 Burning Embers, then Chaos bolting.
(also during boss fight using doomgaurd and such.)
rinse and repeat.
Here is my wow armory for a visual of my currently equipped gear.
http://us.battle.net/wow/en/character/area-52/Frent/simple
 
I guess other then if i'm doing something majorly wrong, a few specific questions,
 
1. what lvl of mastery/multistrike/crit should i aim for potentially?
2. How to most effectively use havoc in fights like Archie?
3. If i run GoSac, does it matter what pet i Sacrifice? ( i know depending on which you sac you gain a ability i've been picking felgaurd for the extra interrupt just in case its needed at some point. Does this effect dps?)
4. When is the most effective time to use dark soul?
5. The standard cool down seems simple but i generally feel sometimes i'm doing it wrong. am i? 
 
Those were some general question but overall any help with my dps would be extremely helpful. 
thanks ahead of time 
F
*Also if there is any other information i can try and provide to help with the analysis please let me know and ill do my best.