I like to think of it as the interest rate you would require to invest in the asset, given its risk profile. There are several ways to estimate the discount rate, but one common method is the weighted average cost of capital (WACC).
In my last role, I worked on a project where we had to value a mid-sized manufacturing company. To determine the discount rate, we first calculated the company's WACC, which took into account the cost of debt, cost of equity, and the proportion of debt and equity in the company's capital structure. We also considered the risk-free rate, the company's beta (a measure of its systematic risk), and the expected market return. By adjusting these factors for the specific risks associated with the company and the industry, we were able to arrive at an appropriate discount rate for the DCF analysis.
Keep in mind that the choice of the discount rate can have a significant impact on the valuation, so it's essential to use a rate that accurately reflects the risks and potential returns of the investment.