Clear, consistent, and predictable consequences

Why should I do it:

It provides student with comfort and limits
You remain in control of the environment
 

When should I do it:

When a student breaks a rule or whose actions are disruptive enough to require a formal consequence
 

How do I do it:

Always provide consequences to students in the most non-emotional state possible. If needed, take a time out for yourself before implementing consequence
Be brief. Use fewest words possible to explain consequence
Give a consequence for the behavior every time it happens.