chris | arnold
If you're not keeping track on your website and your marketing stats, you won't have any idea what's successful and what's a waste of time. Measuring success allows you to make a valuable decision to adjust your approach to something or to scrap it altogether and put your efforts into more worthwhile pursuits.
There are a lot of free tools and packages that can be used with digital marketing, and many systems have them built in. The most obvious one for a website is Google Analytics as it's free and enterprise level. Many third party tools for email and social media are also available.
There's a lot of data to look through in these packages, especially web analytics, so try to pin-point the metrics that have meaning and allow you to make decisions based on the results you find.
Always benchmark your starting position so that you know if things are improving or not when you start an activity.