What are proper techniques to induce crystallization from a saturated solution?

Question

(Select all correct answers.)

Allowing the solution to cool down.
Scratching the outside of the container with a glass rod.
Seeding the solution.
Adding a solvent that lowers the solubility of the target compound.
By adding a boiling chip to the saturated solution.

Answer 1

I've been told that both scratching the outside and seeding can cause crystallization, but don't take my word. I'm not totally sure.