Conventions that help later.
NAMING DATABASES
Descriptive of the site or application: shop, blog, crm, staging.
Not db1, db2, or the date you created it.
FOR SEVERAL SITES
Include something identifying the site: mainsite, clientA, shopng.
The prefix already identifies the account, so the rest should identify the site.
NAMING USERS
Match the database where possible: a user called shop for the database called shop.
That makes the mapping obvious in the cPanel list.
FOR STAGING COPIES
Name them clearly: shop_staging rather than shop2.
The most dangerous mistake on a multi-site account is working on the wrong database because the names were ambiguous.
TABLE PREFIXES
Changing the default table prefix at installation is sometimes suggested as a security measure. Its benefit is modest, and it complicates later work.
If you do, record what you used.
DOCUMENTING IT
A list: site, directory, database, user. Kept off the server.
Ten minutes now saves considerable confusion later.