From StrategyWiki, the free strategy guide and walkthrough wiki

Heart piece locations for The Legend of Zelda: Oracle of Ages.

Description	Necessary items	Picture
In Labrynna (past), after you get the shovel, dig the stones before the black tower to get to the first piece of heart.	Shovel
In the Maku Road (past) in the room with two Stalfos solve an easy block riddle to get to this piece of heart.	none
After going into the first dungeon and getting the power bracelet, lift the stone south of the Yoll Graveyard (present). Take the piece of heart then.	Power Bracelet
Near the Wing Dungeon (past). Outside its entrance go west, north, west, south, south. Burn the tree and find it in the cave.	Ember Seeds
At Talus Peaks (past), go into a cave where the next piece of heart lies. You reach the cave by going left from Labrynna, then up where you have to jump over the hole.	Roc Feather and Power Bracelet

Other pieces:

• Get one from Maple. Use the Maple's Ring to see her more often.
• Get one from a Gasha tree. Use the Gasha Ring to increase chances.