So here's pretty much exactly what I do on Brutallus. It's a tank and spank so I can do this perfectly here. Though on other bosses, it's something very similar anyways. Probably just more interrupts and resets, and different consumables.

Part 1: Consumables

[Elixir of Demonslaying] - 115-120 dps, by comparison [Flask of Relentless Assault] is a 55 dps item.

[Haste Potion] - 50 dps

[Spicy Hot Talbuk] - 25 dps, by comparison [Warp Burger] is a 20 dps item.

[Scroll of Agility V] - 20 dps

[Scroll of Strength V] - 10 dps, not as good for rogues as others, but a small boost and usually cheap

[Drums of Battle] - 20 dps, well this is just mine's and other LW's buff for the party.

[Thistle Tea] - 8 dps, this is another pretty small boost. But it's cheap, I don't use healthstones anyways in this fight, and does help me smooth out my cycles. Usually only wind up using only 1 in the fight since I pop it later in.

Part 2: Slice and Dice

This is the bread and butter of a rogues' damage. It should be prioritized above all other attacks. Keeping SnD up 100% is pretty much essential for maximum dps.

What I start off doing is a 2 point SnD. Then 5 point SnD. Then that eases into my 5s/5r cycles.

Again I stress this is the priority above all else. Even I ran into times where I'd would normally be Rupturing in my cycle but found myself to be energy starved and SnD won't last. So I just go fuck it and reset the cycle, 5 point SnD then and there to start over.

Part 3: Rupture

My other finisher for the most part. When Slice and Dice is safely up, I load up for 5 point Ruptures.

This is merely a secondary move to blow extra combo points on.

Part 4: Cooldowns

As for CDs, Blade Flurry, Adrenaline Rush, Haste Pots, Drums of Battle...

Here's a little chart I made for all our DPS'ers on Brutallus. Can use it to better track your progress on this boss across multiple raids. Compare yourself to others too. Track overall raid dps.

The number in the parentheses is the number of burns that you got for the fight, which affects dps to various degrees. You can also click on the top headers to sort by that column (does not work in Chrome yet).

Anyways, have fun with it.