what to do immediate steps to reduce First contentful paint time on my website?

I am Thiyagarajan from India, I came to know this StackOverflow site is sharing many useful suggestions to beginners, skilled persons, and developers my question is what immediate steps to take for minimizing First contentful paint, my site is taking more time to open so bounce rate also more, please suggest examples or some screenshot methods , hope I get the reply at the earliest (i tried, compression method of all images, avoid codes, etc ) is any suitable plugin (free version) available? thanking you Thiyagarajan