Some ideas that I use:

• Deep breathing
• Reminding myself how important my peace is to me
• Assess the importance of the person to me – if the person is not important for me I would remind myself not to waste my time and emotions on the person
• Overcome my inferiority by focusing on my strengths
• Visualize the turbulence that anger causes as waves in a storm and visualize the still waters underneath the waves to restore the feeling of calm

Hope this helps

Regards