Your adventures in Cataclysm truly open up once you reach level 85, and there are a lot of things to keep your hands full once you reach this stage. You can play your version of In-Game Tycoon by dominating the Auction House. You can hone your skills as a PvP god in Arena and Battleground play. Or you could take the route taken by millions of your peers and allocate 2-3 nights towards conquering all the dungeons and raids the new expansion has to offer.
There are currently 4 raid instances in Cataclysm (Blackwing Descent, Throne of Four Winds, Baradin Hold and Bastion of Twilight) with a brand new one called Firelands destined to hit in the coming months. But, for anyone that is relatively new to the game or who has spent most of their end-game time doing other activities, stepping into dungeons and raids can be an intimidating experience, especially with all the elitist players out there who look down on anyone without a Tier 11 piece to show.
So, how do you start small and build your way up in a game that requires so much time investment and careful attention to detail to pull things off? It may seem overwhelming at first, but the truth is that if you start small and work your way up to the hardest, most time devouring content in the game, you'll quickly find that there are many ways to take on this content without getting completely destroyed each time.
You should endeavor to play with a group of like-minded and responsible individuals. Most of the time people think way too far ahead. Or they want to take the shortcut to epics and stick with already geared players, hoping to hitch a ride on the Epic Express. Unfortunately this will never work, as you don't learn anything this way. A more reliable way is to find a group of players on the same skill level as you and work your way slowly but surely to the top.
Secondly, you shouldn't expect results from the get-go. If you're still new to raiding, you will have to be patient. Wipes will inevitably happen so the correct mindset to adopt is a never give up attitude. Try and try again until you finally reach the finish line.
You will also need to do some research of your own instead of stepping into an instance with nary a clue of what's going to happen. With the vast amount of resources available on the internet, this shouldn't be a problem.
Keep these tips at the back of your mind and I guarantee you will achieve the success you're looking for in your raiding adventures. Good luck!