Got asked about this twice in the past week – here are two very good videos about basic startup metrics and their application to your business.
Dave McClure at Seedcamp 2009 about “startup metrics for pirates”, a talk he has given in lots of places. It’s a good and fun overview of what you should think about and look at.
and the accompanying slides:
And Ryan Carson of Carsonified with a more direct, and very numbers-focused talk from last year. He goes through a very detailed example, explains concepts like CAC, churn, lifetime value, and will give you an idea what unit economics are all about.
He talks about this spreadsheet, which you can copy and play around with easily, giving you a good idea of what your own numbers can look like.