Don’t raise your voice in front of the Prophet ﷺ. Imām Mālik رحمه الله would say: ‘Whoever raises his voice whilst the aḥādīth of the Messenger of Allāh ﷺ are being narrated, it is as if he has raised his voice in the presence of the Messenger of Allāh ﷺ himself.’
All believers are brothers.
If two parties of Muslims are quarrelling, try being the arbitrator and solve the conflict.
Two groups shouldn’t mock each other; it is possible one is better in the sight of Allāh than the other.
Don’t call each other names.
Refrain from thinking bad of other people.
Don’t spy on one another.
We have all been created from one male & one female; our differences in appearance are merely so that we recognise one another.
The best and most honourable in the sight of Allāh is the one with the most taqwā.