It really depends on your business goals, but generally, at least, you should track the following:
1. Cost per click (CPC): This is the amount you pay for each click on your ad. It tells you how expensive your ads are, and how much you’re spending on each click.
2. Cost per acquisition (CPA): This is the amount you pay for each new customer you acquire. It shows you how much it costs to acquire a customer, and how efficient your ads are at generating conversions.
3. Conversion rate: This is the percentage of people who click on your ad and then go on to complete a conversion action (e.g. filling out a form, download, purchase, or sign-up). It tells you how effective your ads are at drawing people in and getting them to take action.
4. Traffic sources: Which websites are sending you the most traffic? Which keywords are driving the most traffic to your website? Which ad campaigns are generating the most conversions?
Google Analytics is a free tool that you can use to track your website stats. It will show you how many visitors you are getting, where they're coming from, and what pages they're viewing.
Here's related information that you may find helpful – Internet Marketing and Business Glossary/Terms for Beginners that might help you to strengthen Digital Marketing knowledge.
P.S:
You are currently on the Digital Marketing Forum page; for more information on various topics that may be helpful, please visit Blog Posts (button below) and [share any content post you love] with your network.
[Want to grow & stay ahead of your competitors? - use these e-Newsletters to your advantage!]
[If you have any specific questions in mind, please drop a mail and I will answer through a post at the earliest possible time]. Check this forum frequently for fresh posts.