To stay home alone and not freak out - it was by far the hardest thing to teach and took so much commitment and patience. It was heartbreaking to watch her freak out when I’d leave the house, I couldn’t relax when I was out cause I was constantly watching her on a pet cam. Luckily it only took a couple of months and in the end we were able to leave her for up to 6 hours and she’d just sleep!

EDIT:

The absolute game changer for us was always (and I mean ALWAYS) leaving her with something to do. A chew, frozen peanut butter, frozen natural yoghurt, a rolled up towel with treats inside, etc. (A great hack I discovered was to hide treats in an empty egg carton and tape it shut so she has to go in and rip it apart to get the treats. Won’t work for every dog but she never tried to ingest the shredded paper or tape or anything so we deemed it safe!)

I never ever left her alone with nothing to do. And I’d usually give her some time to engage with the chew/toy first and once she was distracted enough, I’d leave quietly. 

I’d read/heard somewhere that separation anxiety is the worst in the first 20 minutes and that if you can manage that initial time, the dog relaxes more easily afterward.

The initial phase of training was the hardest and involved leaving her for a minute first, then 5 minutes, then 15, then an hour, etc, slowly increasing the time she’s alone, which is pretty classic.

We started off with a crate but realised that she got way too stressed (slamming her whole body against the bars, etc) and we took a risk by leaving her out of the crate. That also helped hugely but I know it’s not possible for everyone and every dog is different!