Go into the defend against the dark arts classroom after the lesson has finished(when your wandering about in the castle). At the far end of the classroom there is a door and to the right of it on the wall there is a balcony and on it lay about 10-20 beans. The way to get up there is by jumping on the chair just below it and jamming yourself onto the top bit of it(the place where your head goes). Then jump onto the balcony and there is your beans!
Hope I Helped
Happy Gaming ;-)

Maximizing Wingardium Leviosa

To maximize Wingardium Leviosa after you get three shields, take the big block you find on the second level of the Forbidden Forest everywhere with you on the level. You will eventually maximize the spell. This can also work with almost any other spell.

Shield

When you need the shield to the right of the starting place, use Wingardiun Leviosa on the stone block and take it to the original starting place. Go to the right and place it. Note: The block must be under the shield or it will not work.

Refill Harry's energy

If you get a character/friendship card, stand by Ron or Hermione if you are Harry to refill your energy. You can stand by both of them to refill it faster.

Defeating Voldemort

First, Jinx all Voldemort's skeletons. He will cast Abvra Cadabvra and you must move the energy ball over the skeletons. He will then pick up the grim reaper statue and make it float around. Dodge it and on about the third time it is thrown at you, it will get stuck in the ground. Move the energy ball over it, and it will lose a wing. Do this two more times and you will win.

Collector card bonuses

Successfully complete the indicated card set to unlock the corresponding bonus:

20 House Points: Successfully complete the "Beasts" card set.
20 House Points: Successfully complete the "Vampires" card set.
20 House Points: Successfully complete the "Giants" card set.
20 House Points: Successfully complete the "Goblins" card set.
Extra Endurance for Harry: Successfully complete the "Quidittch" card set.
Extra Endurance for Harry: Successfully complete the "Wizards" card set.
Extra Endurance for Hermione: Successfully complete the "Witches" card set.
Extra Endurance for Hermione: Successfully complete the "Hags" card set.
Extra Endurance for Ron: Successfully complete the "Dragons" card set.
Extra Endurance for Ron: Successfully complete the "Classical Beasts" card set.

After you clear the prefects bathroom room & go through the rest of the level in the basement go back into the prefects bathroom from the underground areas and you will find the bath tub empty. Drop a cauldron onto the light area on the tub floor and a secret room will open with a shield. This was the last shield I needed to have all 38.