bro, weneva, you advertise on adwords, always make sure you put an optin form for email ids, & phone numbers(if possible), use exit traffic negotiator to understand why they are leaving, or if possible try providing them live support using craftsyntax(use forced invitation).
This really helped me in generating my leads database, plus i had their phone numbers in hand. Obviously i paid for the traffic, so i wanted atleast that much data, & once i had the data i realised, why they left, & started mailing them with some exciting offers, so even though they left, most of them gave me their contact details & valuable feedback, When you pay for traffic, this is something you should expect in return