#1 - #2: To the left where you first start out, they will be on a bridge by a Mallet walrus guard.
#3 - #4: Further up the same boat are two clues on top of the mast. Hit the base with your cane so they fall down.
#5: Sly will first spot a ladder that will aid in your quest over the gate. A clue is at the bottom of this ladder.
#6 - #7: Near the front gate are three trees and a hanging rope. Two clues are on top of the trees. Use the rope to obtain the second clue on the highest tree at the end.
#8 - #9: Now go the opposite way down the rope and land on a high Earth pile for these two clues on top.
#10 - #11: Past the searchlights after hopping over the front gate are two stone head statue things with a clue on each.
#12 - #13: After you confront a welding walrus guard, there will be clues at the edge of a waterfall.
#14 - #15: After the first waterfall, you will see a second on up ahead with two clues resting of the risen stones above the water.
#16: By this area's vault is a clue bottle hopping around near the broken fence and to the left of it.
#17 - #18: Climb up the hanging rope next to the key at the end for two clues on a high tower.
#19 - #20: Continue across the rope for two more clues resting at the top of the light tower at the end.