For fun, let's look at the other side of the coin--how to guarantee you'll be ignored.
Write a canned subject line.
"Cut your IT costs with virtualization!" "Free Seminar!" "Get your V!agra now!" All of these (and probably many others that you can think of) guarantee that your email will be ignored. As a free bonus, many of these might even help your email go straight to the SPAM folder!
Lots and lots of images.
Granted, images won't guarantee a trip interrupted by the SPAM filter, but they certainly help. At worst, your leads' email programs don't render them, and you end up with ugly images. At best, your leads open your email and roll their eyes at the "artwork". Either way, you're well on your way to the Delete key.
Write only about your product or service.
You and your sales team have spent hours and hours developing sales-y content; this is the perfect place to use it! It doesn't matter at all that your lead has already seen this on your website. It doesn't matter that it provides zero true value to help your lead solve their problems, it helps you get your message across! Right? Right? Well, okay, so maybe they'll tune it out immediately, but it's a great way to pat yourselves on the back while turning off your leads.
Make it look exactly like a newsletter.
If your newsletters already don't get people's attention, use this opportunity to try them out again! And the more impersonal the better, so that your leads truly don't feel like you've given any effort to nurturing them. Unsubscribe link, here we come!
Don't include one of those silly calls to action.
And certainly don't link it to a landing page! If your leads make it through your subject line, many images, and sales-y content, you definitely don't want to make it easy to follow up with you! For that matter, don't include a real reply-to address either. Hey, if your leads can't figure out how to connect with you, they don't deserve to give you money.
But seriously, folks, the bottom line is that you need to provide good, useful content with a compelling subject line, a personal message, and a sound late-funnel call to action. It's going to take more work, and you'll have to actually provide value, but you'll end up with better leads and more customers in the end.