I'm sure some people might think this is common knowledge
but here it is :
It helps if you have more than 1 good geared level 80.
1.Join a group and inspect people and make sure they need some trinkets and other important items from ICC 10/25.
2.If you have the item they need DON'T equip it,get a lower GS one.
3.Roll for the item and hope you win.
4.If they don't whisper you to buy it,then you whisper them.
This is luck and server dependent but i made 200k in 1 month only by doing ICC 10 and 25 with 2 level 80 Chars.
Please don't flame its my first post
Example: You have the Whispering Fanged Skull but you equip another trinket so when you go ICC 10 you can roll for it and hopefully sell it for more than 5k gold ( I sold mine for 8k )