I've been raiding as a warlock for most of the game now, and have seen nearly every boss downed so I wanted to give some tidbits on what I do to be a successful raiding warlock.
Step one is to spec your warlock properly:
http://www.worldofwarcraft.com/info/classes/warlock/talents.html?0000000000000000000001250030133200100000000555000512210013030250
This is the spec that I have been raiding with since I hit 70 and I have been extremely happy with it. It is very similar to the DS/Ruin build I used back at 60.
Here is the reasoning behind picking each of my talents:
Demonology
1/2 Improved Healthstone: You want to coordinate with your fellow raiding warlocks so that if possible your raid has 3 healthstones, 0/2, 1/2, and 2/2.
2/3 Improved Imp: You put points in here just to go further down the tree, you should almost never use your imp. (These points may be placed elsewhere if you like.)
5/5 Demonic Embrace: Stamina is almost as good as mana for a warlock. The more the better, and spirit is useless for a warlock. Due to lifetap you will never be resting long enough to get the 5 seconds required to activate in combat regen.
3/3 Fel Intellect: Max mana by 3% isn't great, but every little bit helps, those bolts get expensive when you're in a 20 minute fight.
1/1 Fel Domination: Not key, but very useful on a few occasions. The best occasion being when you die and are battle rezzed, you are then able to summon an succubus and sac it quickly to continue your dps.
3/3 Fel Stamina: 3% more hp is more for lifetaps.
3/3 Demonic Aegis: +30% to Fel Armor is wonderful, the +dmg is nice but the + to healing is great since you lifetap so much. This really helps reduce the strain of healing on you and as such is always a benifit.
2/2 Master Summoner: Goes along with Fel Domination.
1/1 Demonic Sacrifice: Sac your succubus and go to town. Some fights such as Kazrogal and Mother Shrazz it is also useful to sac your felhunter. Kaz because he drains mana and Mother because your gear is gimped.
Destruction
5/5 Improved Shadow Bolt: This is a huge boost to your dps and helps the raid out as well. I believe this is getting changed in 2.4 to boost the warlock only which is a boost to warlock dps so they are reducing the %, but it may hurt the raid as a whole sadly.
5/5 Cataclysm: This is mostly filler, but every little bit helps in long fights. If you are a tanking warlock and cannot pick up Nether Protection then you wont be grabbing this. Grab Improved Immolate instead.
5/5 Bane: Reducing the cast time of your bolts does not reduce the dmg co-efficient so it is a must.
5/5 Devastation: You need to hit 25% crit so this helps a lot.
1/1 Shadowburn: Not used much for bosses but helps boost dps a bit on trash.
2/2 Intensity: This helps in a few fights to get those bolts off even when you're being hit.
2/2 Destructive Reach: Range is always nice but the threat reduction is a must.
1/3 Improved Searing Pain: Filler, you may place this wherever you like. If you're a tanking warlock and not getting Nether Protection then you will be skipping this.
1/1 Ruin: A must for any destruction spec.
3/3 Nether Protection: Helps on a few fights such as Mother. May be placed elsewhere if you like. Do not get if you plan on tanking.
3/3 Backlash: More crit is always nice. This wont proc often enough in raiding for instant cast part to be useful sadly.
2/3 Soul Leech: This is optional, and tanking warlocks will be skipping it. You may place these talents where you like.
5/5 Shadow and Flame: This will boost your overall damage by a decent amount and is one of three absolute must haves for this spec. (DS/Ruin/SF)
If you plan on tanking then the talents that you may want to get instead of Cataclysm, Improved Searing Pain, Nether Protection, and Soul Leech are:
5/5 Improved Immolate: Once you are well geared you will not be casting immolate, but in tanking gear it is a viable spell, and this helps with it's dmg.
5/5 Emberstorm: Since you will be casting things like searing pain while tanking you will want to pick this up. It is also optional to drop 3 points for Improved Searing Pain. Up to you.
1/1 Conflagrate: Good burst damage when needed, pop at the end of Immolate to grab a bit of extra aggro.
This took a good bit to type up so I will be updating it later on. I will later include gearing and finally your spell rotation. Please let me know if you have any comments or questions. I myself never tank so I don't have much experience in that variance of the spec. Hopefully this will help someone trying to get on their feet as a Destruction warlock!