What I've found is that generic e-mails don't work. What I've had success with so far are personalized e-mails followed with a phone call the next day.
Adding screenshots or documents to the e-mail helps to break the ice in the phone conversation.
I don't think there's a secret sauce though, you have to adapt the script/pitch to every customer.
Like Rajen said it depends on your product and the type of leads.
A strategy I use is to call in 1 week to the same type of customers (e.g. Small Business)
Then the next week I'll switch to another type of people to contact (e.g. Universities)
It helps keep the conversations focused in the same week on the same type of customer.
I guess you can call it weekly market segmentation of your cold calls.