Here are a few things you can do to prevent or help with separation anxiety:
1. Don’t cuddle the anxiety!. ( if your dog whining and stressed about you leaving don’t baby talk and pet them, because you’re nurturing that state of mind.
2. Drain your dog’s physical energy.
3. Crate train. Increase the time slowly, don’t rush.
4. Place work: ask the dog to stay in a certain place, this prevent your dog to following you all the time.
5. Don’t let them on furniture next to yourself for a while.
6. Provide clear structure
7. Be Patient!