Tried and failed at the controlled crying method of doing this. Finally bought a sleepy tot so she could keep it in her mouth all night. Im now not planning to take it off her until shes 7 . Honestly, whatever works, use it.
my dd is 2.6 and cannot sleep without a dummy, she only has it at bedtime so does not walk round with it hanging out of her mouth. when she is old enough to understand will tell her that i will give it to the dummy fairy