Addons to have

Hereunder follows a list of addons that will greatly increase your game awareness. I recommend you try them out in a normal battleground before stepping in to a rbg. Of course if you have other addons that supply the same sort of information, be my guest all I know is that this is what works great for me. (edit: in red below are the ones that are vital for doing a better job, in the comments is extra info on lose control and diminishing returns)

1. battleground targets
2. carbonite
3. deminishing returns
4. interruptbar
5. killthehealer
6. omni cc
7. lose control

 Herunder follow the same addons but with some extra info

1. battleground targets (must have)
1. This Addon is vital in rbg's since it directly shows who you are up against. Make sure you set it up so you can see the classes, specs and who is carrying the flag.
2. Another advantage is that you can see the moment they re spawn or when someone is hiding (sneaky rogues druids). very important!
2. Carbonite (optional)
1.  Although this is mainly a quest helper. It also has a great mini map for battlegrounds showing timers on flags where your team mates are (with their names, optional). And even more it shows very clearly where people are fighting. 
3. Diminishing returns (if you don't have this or something similar, your CC is based on luck)
1.  This is one of the things all people tend to forget. And if you don't have it, set up asap because this is a game maker. In a nut shell, all forms of cc have diminishing returns. Meaning: the first time you use for instance a fear the effect is full, but if you fear again within 15 seconds the effect is deminished (1/2) and the third time its even worse (1/4) not to mention a 4 time the target is immune.
2. Now if you consider that quite some spells - although they are different - have a shared diminishing return (i.e. fear and blind). You can imagine how impossible it will be for you to keep track of effective cc's when you are with 4 people that are all trying to cc. This addon Shows you How effective the following cc is and how much time is left on a cc for it to have full effect again, instead of diminished.
3. If you try to set this up, you need to be in combat unfortunately. So try a training dummy. /w me if you have troubles setting it up.
4. interruptbar (are you a caster?)
1. If you are a caster,  you should be fake casting if its appropriate. But how do you know when you can freely cast? This addons directly shows you. If you were able to fake cast and trigger a kick and you were successful, it shows you the symbol of the "kick" spell and a timer until the next is ready.
   
5. killthehealer (optional)
1.  This or addon, (comes in many similar forms) gives enemy healers a special mark above their head so you know which enemy should be your prime. (healers often are)
6. omni cc (very usefull)
1.  This addons shows a more precise timer on your spells. Nothing more nothing less. Great for communicating, and setting up bursts or cc chains. (note this is no subsitute for loose control or diminishing returns)
7. lose control (lightweight and SUPER useful)
1.  This addon Is just as vital as diminishing returns. It shows on your main and focus target if they are cc'ed and what spell it is and how much time left. Make the spells a bit bigger so you never ever have to excuse again for screwing up a sheep or a blind. (saw one tonight again) And in combination with diminishing returns you know if you should better kidney or dance and sap next.

If you have troubles setting these addons up you can /w me if I am around.

Bones =)

P.s. All the addons mentioned above can be downloaded from curse.com I also recommend using the curse client to keep up to date and save you from unzipping and other crap.