Examples of email autoresponder strategies?

I'm searching for some examples / case studies / strategies / advice for crafting an email autoresponder series, with the goal of converting newsletter subscribers into customers of my saas service.

I know, "it depends"... But would love to hear some case studies on this subject.

NOTES:

• My email subscribers have opted in to receive content from us (free guide, periodic blog articles).
• They're not yet users of my saas service. I want to convert newsletter subscribers INTO users of the service.
• I'm a bit hesitant to come off as too salesy, since they had opted in for content (guide, articles), not constant sales pitches (though I'd like to add some kind of "nudge" to increase subscriber>customer conversions).
• This question is not about how to technically set this up. I'm already familiar with how to do this (I use MailChimp). I'm seeking advice/examples on autoresponder content, sequence, frequency, etc.

Thanks in advance!

Okay - the general successful approach that I've seen is a process of:

1. Demonstration that you are knowledgeable in your field. Say that my app is about time tracking. I post knowledgeable articles / links about time management, life hacking, etc.
2. Persuasion that this is a solvable problem. Tell stories about how folks lives got better after they got better at managing their time.
3. Showing that your solution is good. Selling your particular application as the solution.

At the start of the drip-feed campaign mostly (1), little bit of (2), almost no (3).

At the end (and ongoing) the mail is a little bit of (1), (2) becomes mostly testimonials / client stories, and a lot more (3).

Never turn it into a total sales pitch. Since these will kill of the customers who are still mildly interested but haven't got around to purchasing yet.

Patrick McKenzie writes about this a fair bit on his blog (Bias warning: he has a course on email marketing).