Use long term government bond rate as the discount rate.
But first, you must understand the business so that you can estimate the growth of future earnings/cash.
[Full Videos of Berkshire Hathaway Annual Meeting 1996]
[ABOUT - Collection: Warren Buffett]
Whenever, I search up on fund managers that practice value investing. All of them done 1 common thing that is, they study whatever they can about Warren Buffett from his annual letters, annual meeting or even interviews. Hence, I decided to do the same and share it together with all of you so that we can learn and grow together :)
[My 2 Cents]
Valuation is not as important as you think.
What you really need to know is the business.