A couple of items to give you an overview of what you should be thinking about and what you can realistically aspire to.
First, a great infographic from Adobe and econsultancy.com that illustrates just how little is done at the moment (so don't get too downhearted) and provides a few helpful tips.
Infographic: Making Sense of Marketing Attribution by Econsultancy
And a short article on inc.com explaining why marketing attribution should matter to you and providing a bit of follow up reading.
The bottom line here:
- You're never going to be able to comprehensively measure the customer experience but don't let the lack of absolutes put you off
- If you don't plan for measurement in your marketing activities, you'll struggle
- Combine what you learn across channels - online and offline - for maximum benefit