What he said rings true no matter whether you're trying to sell to offline clients or even if you're trying to sell an information product online.
Tell them what to do [in the case of offline clients what you're going to do for them] but not how to do it [in the case of offline clients how you're going to do it for them.]
If you're talking to a prospective offline client the chances of giving them information overload are tremendous.
If you're an expert in the subject, it's easy for this to happen. The problem is, the client is most likely not on the same level as you are.
For example, if you're talking to them about building backlinks, all you have to do is tell them the what, not the how.
"You see Mr. Business owner, I'm going to have some backlinks built to your website. Backlinks are important in order to help people find your site when they're looking to buy [whatever your potential client sells.] I'm going to make sure you have high quality and relevant backlinks to your site to try and drive more eyes to your website and make more sales for you putting more money in your pocket."
They don't need to hear that you're going to get links on PR 4+ domains.
They don't need to hear that you're going to be using a linkwheel.
They don't need to hear that you're going to be using social signals such as Twitter, FB, Google+ etc...
They only need to hear that you're going to provide them backlinks, get them more traffic to their website, and put more money in their pocket as a result.
This was just an example for someone offering SEO services.
It doesn't matter what service you're offering. Stop losing sales and making clients eyes glaze over because you're telling them what you're going to do AND how you're going to do it.
It benefits neither one of you if you go into specifics of exactly how you're going to do it.