How to minimize primer dimer formation?

The melt curve analysis shows high primer dimer formation: why and what can I do?

Primer Dimer

Primer dimer formations are non-specific products and can be minimized by constant cooling during PCR setup.

It is completely normal that in negative samples, for example, the negative control (NC), the primer dimer can be higher compared to positive samples, for example, the positive control 1 (P1).