Star 2: Ride Big Boo's Merry-Go-Round
Enter the wooden shack to the left of the Haunted House, then follow the one-way path to the Merry-Go-Round. Once inside the Merry-Go-Round, defeat five BooBuddies to make a Big Boo appear, then defeat the Big Boo to obtain the Star. 

Star 3: Secret of the Haunted Books
Once inside the Haunted House, jump up the stairs to the second floor. Enter the second door to the left, then follow the path until you reach three green books sticking out of a bookcase. Jump into the middle book, right book, then left book to reveal a hidden passageway that will lead you to the Star. 

Star 4: Seek the 8 Red Coins
To get this star you have to get the 8 red coins. Here's how:

You can collect the eight Red Coins in any order. First Floor: One is located in the  room with the piano. From the inside entrance of the Haunted House, enter the first door on the left, then walk next to the piano to make it come to life. Once the piano begins to jump around, collect the Red Coin that was under it. Two are located in the room with the picture of the Boo Buddy. From the inside entrance of the Haunted House, enter the second door on the left, then jump up onto the two
bookcases and collect the Red Coins. One is located in the room with the black pit From the inside entrance of the Haunted House, enter the first door on the right, then walk over to the center ledge with the Red Coin on it. FYI: If you fall down the pit, you will appear next to the Merry-Go-Round room. Second Floor: One is located in the room with the red wire net. From the inside entrance of the Haunted House, jump up the stairs to the second floor, then enter the first door to the left. Carefully walk across the wire net to reach the Red Coin on the other side of the room. Two are located in the room with the coffins. From the inside entrance of the Haunted House, jump up the stairs to the second floor, then enter the first door to the right. Avoid the Spinning Eye enemy, then enter the room with the six coffins. If you walk in front of a coffin, it may temporarily rise up. Walk in front of the center coffin on the left side of the room to locate a Red Coin, then walk in front of the first coffin on the right side of the room to locate a Red Coin. One is located in the room with the hidden floor panel. From the inside entrance of the Haunted House, jump up the stairs to the second floor, then enter the far right door. Walk to the room to the left and collect the Red Coin. Star 4 will appear on the second floor where the moonlight shines through the window. 

Star 5: Big Boo's Balcony
Once inside the Haunted House, jump up the stairs to the second floor, then enter the second door to the right. Jump onto the wooden platform in the corner of the room, then Wall-Jump off the right wall onto the ledge above and enter the door. Go through the double doors on the right side of the room, then defeat the Big Boo outside on the ledge. In order to get to the Star, you need to Long Jump from the balcony to either of the two window peaks, then jump up to the top of the house and get the Star. This can be very tricky and will require a lot of practice! 

Star 6: Eye to Eye in the Secret Room
Collect the Vanish Cap on the second floor of the Haunted House, then enter the room that led you to the Big Boo on the balcony. Before the Vanish Power wears off, run to the other side of the room and jump through the picture of the Boo Buddy. Once inside the secret room, defeat the Spinning Eye enemy to obtain the Star.