I'm already worried about hair loss. What are some ways to prevent hair loss?

Lately, I feel like I'm losing a lot of hair. It seems like my hair volume has decreased compared to before, and I'm already worried about hair loss. I want to prevent it before it fully starts. I bought a hair loss prevention shampoo, but I don't know what else I should do to prevent hair loss. Does anyone know if there are foods or supplements that directly have a positive effect on preventing hair loss?