Conversion rate, organic traffic, leads generated. In that order.
The most important metric is conversion rate. What percentage of visitors take your desired action. Enquiry, booking, purchase. After that: organic search traffic. How many people find you through Google. Then bounce rate and session duration. How long people stay and how many pages they read. PageSpeed score. Number of leads or enquiries per month. Cost per lead if you run paid ads. Use Google Analytics 4 for on-site tracking. Google Search Console for search data. Focus on the metrics that connect directly to revenue. Vanity metrics are not a business.