Every emotion we feel is because of the thought we have. Emotions then trigger action and behavior.
You can’t feel angry without a thought attached to the incident (which is neutral).
It is always a thought attached and which thought is assigned to which incident is coming from our belief system and conditioning.

It is effortless to say that we should have positive thoughts but
We cant monitor the countless thoughts going through our mind, but we can for sure deconstruct these thoughts later.
process of deconstruction
Be aware of the thought behind the emotion
Be mindful of the belief, the story, attached to the incident.
Be willing to deconstruct that thought and see through the mess of beliefs.
If a child comes home with fewer marks, low grade in her maths exam, then
Be aware of the thought behind the feeling of Sadness.
Be mindful of the story behind the thought that fewer marks means, bleak future, low academic grades, no approval from society, etc. etc.
Be willing to deconstruct he story — Is it real or is it just the fear of future. Are you attaching your child worth on the result? What can you do best without connecting any story to the incident -you may get some external help, maybe talking to the child about his feelings with any judgment.

Be conscious of the thought behind emotions and story, beliefs attached to it.