I too had problems to start with, but I found that there are a few key things that work for me that aren't apparent in videos or really touched on much. Take'em with a grain of salt, as your mileage may vary.

1. I use a Paladin healer. I've found that they are far superior to the other choices. Generally speaking, you're going to win or lose in the first ~15 seconds of an engagement. Either you were able to burn someone down quickly and make it 5v4 or they were able to CC/Outheal you and they killed one of your Shammies. With that in mind, I feel that Paladin best complements this quick-win strategy in that they can bubble immediately and just heal heal heal, plus drop BoP on whoever's getting raped.

2. I don't use the PvP trinket. I use the +DMG Battlemasters and the +63 DMG Alch trinket from Shattered Sun. I've found that I'd rather have the damage than the ability to stop the CC since for my setup it's very hard to individually activate trinkets--Being an all or none thing, you're basically using 4x trinket slots (potentially +200 total damage) to stop one CC. Now, if it's an AE fear that's one thing, but that's what 4x Tremors are for.

3. My totem macro drops all of the following totems. It is staggered on each toon so that I don't get more than 2x Tremor's ticking at the same time: 4x Tremor Totem, 4x Searing Totem, 1x Wrath of Air Totem, 3x Grounding Totem, 2x Poison Cleansing Totem, 2x Mana Spring Totem. I also have one separate button that drops a 4x set of the following totems: Grounding, Searing, Nova.

4. 4x Purge is always my first spell. The difference between a completely debuffed Warrior and a buffed is enough to make the difference between a 2 volley kill and them getting healed/breaking LoS.

5. This is probably the most important thing that I learned over my arena games--It's the tip that easily earned us 100+ increase in rating: Switch targets. Often. Initially don't target the one you want to burn down. Say they've got a Warrior, Mage, and whatever else for dps: Target the Mage until they actually come in and start. As soon as they're committed to an assault, swap to the Warrior. Good teams will already be healing that mage. In the amount of time it takes them to change targets and start a heal you can burn the Warrior down without even giving him the chance to spell reflect.

This continues as the fight progresses. Say they were able to swap and heal--If two volleys doesn't kill someone because of healing then swap to a healer. Continually casting on the same target if they're able to heal through it doesn't get you anywhere--At that point it is only through target switching that you're going to win. Generally, you're going to run out of mana before they will in my experience because you don't have a healing debuff.

Again, this is just my experience and what has worked for me so far.