The first step to benchmark your performance marketing is to use your own historical data as a baseline. This means analyzing your key performance indicators (KPIs), such as impressions, clicks, conversions, cost per action (CPA), and ROI, over a specific time frame, such as a month, a quarter, or a year. You can use tools like Google Analytics, Facebook Ads Manager, or HubSpot to track and visualize your data. You can also segment your data by channel, campaign, audience, or device to get more insights into your performance.