The Star, The Hand and The Heart QuestFollow

Grel'borg the Miser (40,48) Alterac Mountains
Mogh the Undying (48, 44) Stangelthorn Vale
Dagon the Ravenous (59,09) Dustwallow Marsh

1.Star of Xil'yeh
The Ogre has a name, it is in the note, look for him in the Alterac Mountains as others have mentioned. He is patrolling in and out of the keep, so you could see him in different areas. If you can stealth, just wait for him near the entrance of the keep and get him outside. If you are not high enough level you will agro the nearby ogres. At level 45 (rogue) I imp sapped one close to the entrance and ambushed my ogre there.

2.Hand of Dagun
As the note says, you need to find the murlocks that are named "Mirefin Oracles", there are very few of them, but they will drop it. The murlocks are on the islands that are the furthest North East in Dustwallow Marsh. For me the third or fouth Mirefin Oracle dropped it. Go up to the alter and click on the kelp. The giant comes from the ocean, look to the East slightly North.

I am a level 46 rogue, I am guessing the giant would have been a challenge while I was solo'ing him but a priest gave me Fort and a heal in the battle. When the giants health got very low he started to run, so I don't think he heals himself as someone else posted.

3.The Legacy Heart
Have not completed the third part. But sounds like I just need to sap and blind two mobs so I can get my witch doctor. Good luck :)