One thing that we would occasionally do (and I don't know if this is a 'correct' thing or not) is if Odie was whining, we'd go near his crate and mooch around pretending to do stuff but ignoring him. It would often calm him enough just us being near, but we're not actually giving him attention so there's (hopefully!) no positive affirmation of him whining. That was my thinking anyway - he's pretty chill in his crate now and will go in on his own accord and not whine when we're not there.
One thing that we would occasionally do (and I don't know if this is a 'correct' thing or not) is if Odie was whining, we'd go near his crate and mooch around pretending to do stuff but ignoring him. It would often calm him enough just us being near, but we're not actually giving him attention so there's (hopefully!) no positive affirmation of him whining. That was my thinking anyway - he's pretty chill in his crate now and will go in on his own accord and not whine when we're not there.