Database, Table and Column Naming Conventions?

Whenever I design a database,

1. Should table names be plural?
2. Should column names be singular?
3. Should I prefix tables or columns?
4. Should I use any case in naming items?

What are recommended guidelines for naming items in a database?

Check out Microsoft's SQL Server sample databases: https://github.com/Microsoft/sql-server-samples/releases/tag/adventureworks

The AdventureWorks sample uses a very clear and consistent naming convention that uses schema names for the organization of database objects.

1. Singular names for tables
2. Singular names for columns
3. Schema name for tables prefix (E.g.: SchemeName.TableName)
4. Pascal casing (a.k.a. upper camel case)