Do’s
1.  DO perform database maintenance regularly.
2.  DO monitor processor, memory, disk performance and free space, network and key SQL Server performance and log performance counters.
3.  DO place tempdb data files, all user database files and all transaction logs on separate physical disks from each other.
4.  DO allocate adequate memory for SQL Server and monitor Page Life Expectancy to detect memory pressure.
5.  DO have a backup plan and practice disaster recovery. Understand the different types of recovery models and regularly back up databases and transaction logs.
6.  DO allocate enough free space within data and log files to prevent autogrowth.
7.  DO monitor and log long running queries.
8.  DO place a clustered index on all tables in a database.
9.  DO monitor for failed logins.
10. DO configure failed job alerts to send e-mail messages to support staff.

Honorable mention:
11.  DO archive or remove old data from production databases.
12.  DO index temporary tables.
13.  DO use fully qualified naming when referring to objects (db.owner.object and owner.object) in code.
14.  DO use SET NOCOUNT ON in each stored procedure.
15.  DO substitute EXISTS for IN in code.

Don’ts
1.  DON’T allow users or application to access the databases or server as sa.
2.  DON’T allow untested changes in the production environment.
3.  DON’T allow test or development databases in the production environment.
4.  DON’T backup databases to the logical disks where the data files are stored.
5.  DON’T apply hotfixes unless necessary. Make sure to test any hotfixes if they must be applied.
6.  DON’T create stored procedures with “sp_” as the prefix of the name.
7.  DON’T turn on the AUTOSHRINK option on production databases.
8.  DON’T allow overlapping or duplicate indexes.
9.  DON’T allow index hints unless absolutely necessary or table hints unless properly tested.
10.  DON’T over-normalize databases.

Honorable mention:
11.  DON’T allow cursors in code when a set based operation would do as well.
12.  DON’T disable AUTOSTATS for a database unless absolutely necessary.
13.  DON’T allow SELECT * in code.
14.  DON’T allow code that creates fragmentation (such as creating a table with blank VARCHAR or NVARCHAR columns then populate with an UPDATE statement).