How can I tell if I'm working with a savvy business person?
Brushfire: The best sales/marketing/mgmt people I've met are those that take a systems-focused approach. On some levels, this is very similar to designing your db layout, or the user flow through your application.Good sales people design a repeatable process around selling. They investigate the market, build a call list, and execute through the call list. They then refactor based on results. They do not throw shit wildly at the wall and hope something happens.Good management people design business process in similar ways. Customer service is a system. Calls come in, they are processed, logs are created, and evaluations are done quarterly of the system. Apply similar methodology to hiring, to finance, to marketing, to accounting, etc. 
The hardest people to find are those with good strategic vision -- so if this is your idea, you need to be that person.Some of these things are harder to assess than others. Look for people who use data to make decisions, who are 'doers', and who can describe to you the process they plan to take. Look for people who have a track record of these things in other, perhaps non-startup ways.