I occasionally receive emails like these, and I agree with most of this advice. I will add a couple of personal turn-offs:

* Overtesting. I have received multiple emails from different people at the same company with the exact same subject line ("Hey Evan, let's chat"). I am sure this subject works better than the other ones that they tried, but a little variation would make me feel like I am more than a conversion goal.

* Being vague about the purpose of "chatting". If an engineer emails me and saying he or she "would love to hear more about X", where X is something I've done, it's not immediately apparent that they actually don't give a shit about X unless they can hire me. Don't be bashful, just say your company is hiring. At least when a recruiter (or founder) emails, I know what page we're on.