I do have one issue with it though, this line:
1. Establish warmth – Demonstrate you’re not a dick. To do this, it helps not to be a dick.
If you're a naturally outgoing person with a warm personality, then yes, it's not more complicated than that. But a lot of tech people struggle with this..
How DO I "establish warmth" if I'm naturally inwards-looking person that likes listening more than talking?
Showing warmth and that you're not a dick means listening to other people and responding to what they say (In my opinion). That may be an oversimplification.
I went for lunch with my sister a few months ago, she was having trouble making friends and being warm and open to new people. When the waitress came over I chatted with her a little bit and joked around because she nearly tripped as she approached our table. When the waitress left my sister asked me if I knew her - I didn't. She thought I had because of how we were talking to each other. I gave her a tip that she said completely changed how she approaches new people - she was already trying to just listen to what other people say and asking questions when it was her turn to talk but the thing that made it click for her was that I suggested to her that she should try pretending that they're already her friend. That tip made talking to new people easier for her. If you talk to people like they're already your friend then it's easier to be yourself, genuine, and warm and be interested in who they are.
It might work for you - your milage may vary.
[1] http://www.ted.com/talks/ron_gutman_the_hidden_power_of_smil...
The best salespeople always listen much more than they talk, so you are fine there. Of course, you actually have to listen, rather than tune out. If you really listen well, that is a major advantage in sales.
Hmm, I don't know. I think such salespeople may be the ones favoured by the crowd here. Though not exclusively, others have mentioned those that attempt to educate you as being better (IMO that means they're talking more, answering your questions).
I'm not prepared to accept thought that being more likeable translates to better sales figures in general without some hard evidence.
Do companies turn down the best financial offer because the salesperson is a pillock? Can't see it happening much unfortunately.
Smile more often (you don't have to be grinning ear to ear, just any facial expression that has a modicum of happiness).
Touch base with people whenever possible.
If you're a naturally inwards looking person that likes listening more than talking you've got half your problems solved, all you need to do is start asking questions and be sincerely interested in what they have to say. The only thing people love more than talking about themselves is having someone to listen to it.