Your first task is to get gear so that you don't walk around naked. Your first target is
Northrend Vanguard, which is done within one day and will net you most of your starter gear. You should have a steady amount of gold through the quests, so visit the AH and search for cheap BoEs. There are blues and epics that sell for as little as 50-150g. At this point, you should be around 3k GS. Do some ICC rep farms so you can get your ring. You can also buy some of the more common ICC trash BoEs, if they're good for your class/spec, relatively cheap. Start farming HC dungeons and FoS/PoS normals. You should reach 4k GS within a week or so. Keep going until you reach 4.5k-5k GS and don't forget to do the weekly raid quest "X must die!" from Dalaran. From that point, you will be full T9 and you should also gem and enchant your gear. Then you'll start with the boring part of the game - look for ToC PUGs and a guild that is willing to take averagely geared 80s like yourself to raids. Eventually, you'll start doing VoA and ICC normals. Don't expect much progress in ICC at first. Although the minimum GS for the raid is 4.8k, you will not get past PP in such gear. At around 5.5k GS, you will start progressing deeper into ICC, hopefully to your first LK kill. Keep gearing up until you get LK on farm on 10/25. Then you will start doing ICC Hc and Ruby Sanctum. End-game comes when you have steady progression on ICC Hc, aiming for Bane and LoD, and when you have Ruby Sanctum on farm and attempting HC.