Something that I think is really important when it comes to your marketing (particularly your tracking) is to know these key metrics to help you make better decisions.
1) Cost Per Acquisition
2) Return on Ad spend
3) Your turnaround time
4) Lifetime Value per Customer (Projected Lifetime Value)
At the end of the day the return on your investment is what you will most likely want to pay attention to because if you are able to get cheap acquisitions but your lifetime value is really low then you will burn through your customers making it more and more expensive over time to acquire new customers.
So one way to increase your return on investment is to spend a very large amount of time and energy figuring out how to increase the lifetime value of a customer.
Acquisitions are great but only to the extent of how long customers stay around.
Don't forget to pay attention to the customers you already have and how they can help grow your business.
That part of your marketing is just as important if not more important than the acquisition of new customers.
A company that I remember reading about that did really well with this strategy is the company Zappos.
These are just a few thoughts that I have when it comes to marketing your business or brand.