Yikes...the busier I get the harder it is to keep all of my clients/potential clients straight. Any tricks that you use to ensure you follow up with who you need to follow up with? Different folders for Potentials/Booked/Old Clients?
Gmail allows stars, filters, labels, galore. Any email that requires any task that I have yet to complete stays in the inbox. If I've completed everything, its then archived. Any emails which I need to call gets starred.
Partnered with Things (mac app + iphone app) allows me to make a task for everything.
I don't use Gmail for my stuff, but I do use Apple's iCal app extensively. Anytime I need to take any action, or do a shoot, etc... I always set a reminder for myself with an alert in iCal. Entries such as "follow-up call with _____" and "SHOOT: ______" and "CONSULT: ______" are very common in my iCal.
There's no way I'd remember all the crap that's going on without putting it in a calendar.
Seperate Apple Mail folders for "inquiries" + "existing clients". iCal for managing dates/times/bookings/etc. Seamlessly integrates with my iPhone. Couldn't imagine a better solution.