Harry Potter and the Sorcerer's Stone Cheats
Rummage through every desk in the classrooms. They contain Beans, Cauldron Cakes, Pumpkin Pasties, Stink Pellets and even Wizard Cards.
There are mean looking statues of gargoyles all over the teachers' quests. Light Lumos in front of them and they will reveal a hidden path.
How to beat Trolls
There will be multiple encounters with trolls. Locate a Spongify tile and shoot Spongify at it. Wait for the troll to run at you. Then, jump on the tile towards the troll. He will hit the tile then hit himself on the head.
Secret passage to the 4th floor
Go out of the common room and into the main room. Turn right and crawl under the bookshelf. This area is also in the Chamber of Secrets.