Starting in ER (BB Bank, Grocery Retail)

Congrats on the job, always nice to see people make the escape from audit.

Assuming that you are joining an established analyst vs a new one looking to launch, I would reach out to the team and ask what you can do to best prepare leading up to your start. Ask for access to their research and get familiar with their writing style and companies under coverage. Any recent initiations will be great to read as those are the more in-depth research pieces. Plus, they probably have some sector piece(s) they put out for the 2021 outlook that should give you insight into the investor debates in the sector recently. 

I wouldn't be too concerned about technicals beyond the basics. Again, assuming you're joining an established team the models will already be built. Maybe ask if they can send you any before you start to become familiar with them. Valuation is always helpful for your own development, but truth be told analysts use PE 99% of the time on their retailer valuations and there's just not too much to study on there. 

Overall, I wouldn't stress yourself too much. Take some time to refresh between gigs and just be sure you hit the ground running energy and attitude wise. If they are recruiting you from a non-ER background they will understand that there is going to be a learning curve at the start. And just an FYI, first few earnings cycles will probably suck being super busy and feeling like you have no idea what you're writing about. Happens to everyone scaling into a new coverage.