1. A red hermione-shaped purse: This is the first item she throws, aiming for the knot on the tree trunk.
2. A pair of her own earrings: She throws these after the purse misses the knot.
3. A small, blue-and-silver locket: This is the final item she throws, which finally hits the knot, causing the tree to let them pass.
It's worth noting that in the book, Hermione only throws the locket, and the willow is more susceptible to a simple "good hard kick" from Ron.