Here's where you look at your items in the Items List and decide what's hot and what's not.
To find out how many of a particular item you sold, print:
To find out which items you sold to a particular customer, print:
To find out which customers bought a particular item, print:
Note: Once you settle on the list of reports you like to run every month, consider creating a report batch for them. Refer to What's a Report Batch? for more information.