How To Reduce Server Response Time Of a Website?

Hello everyone, i’m a webmaster of my website , a portal of Indian music. I’m trying for many days to reduce the response time of server. In google’s page speed insights, it shows my site take 0.4 to 0.3s DCL to load from mobile and from desktop, it takes 0.9 to 0.8s DCL to load. I think it is good loading time but google still suggest me to reduce server time response.
I can’t reveal the clue to solve this. So if anybody know the way to solve this, then please tell me.
Thanks