In Whoville, there are small children who are guarding presents that give you 10 points. They are dancing to the music that the little horn thing beside them is making. If you shoot the kid with the Rotten Egg Launcher, the kid will go away. You cannot get the present while the music is playing. Slime the horn with the Slime Gun, then you can get the present.
This is the toughest sleigh part to collect. Throughout Downtown Whoville, there are some sort of snowplows driving over the snow. Get behind one of them, then wait for the door at the back to open and shoot it with your Rotten Egg Launcher. This will make it explode, revealing the part.
To enter the Clock Tower, get all the blueprints for the Jet Spring. After that, equip it, stand on the "lift", and shoot upwards towards the closed hatch. The Grinch will automatically grab the hatch's lever and open it.
To get the Sculpting Tools in Whoville, enter the Town Hall. TAfter that, go to the room across where the statue is located to find see a rug or cabinet type thing on the wall in the back of the room. Approach it and press ACTIVATE. It will hold on to the cabinet. Move it to the side. Press ACTIVATE to pull out the safety, then jump, do a pancake on it, and the tools will pop out.