While importing items, look at the Barcode Handling section on the Settings tab. Add a Starting Item Barcode and select Always Assign New Barcodes

You probably used a quick report last time! 

You can set copies to in processing (i.e. checked out to the In Processing system patron #7) if they're in your library but aren't ready to be placed on shelves yet. They will automatically be marked as unavailable in Researcher, but you can just hide them if you'd like. In Researcher Preferences, check the In Processing box on the Auto-Hide tab

If you turn on Automatically Retrieve Cover Art During Idle Periods in 

Alexandria will search for cover art based off of ISBNs and add it as it's found. You may also want to check the ISBN of items without cover art to ensure they're accurate.

Ensure that your import file has the correct site code for each copy. If a copy's status unexpectedly changes to In Transit when bookdropped (checked in) instead of Available, it may be assigned to the wrong site

Title Assistant uses Z39.50 servers to search for items, so you may need to add more. Check out the 

page for a list of resources you can use to bolster your Z39.50 list in Alexandria. You'll also find instructions on adding servers, creating sets, and more.