I'm gonna start with a couple of personal assumptions and truths so we're all on the same, er, page... yeah. See what I did there?
You're a good writer or on your way to being solid. Making friends with the most powerful people in publishing means nothing unless you've got the chops. Qualities I've noticed from such people: you spend more time on actual writing than anything else in connection with it. You're continually learning and pushing yourself to do better. You have stuff you've written that embarrasses you (even recent stuff--hell, especially recent stuff). You have a sizable collection of rejections. You read. In other words, you take writing seriously. At least as seriously as this guy.
You want to sell your writing and are willing to go to conventions, talk to fans, develop a public persona, survive the haters, and have people know you who you don't know. Oh, it really helps if your family is cool with all that, too.
Networking is less about selling books and more about building your name, brand, and making industry contacts. That's what leads to contracts and a career, which leads to selling books. It's a winding path indeed from Networking to Selling Gobs of Books. Otherwise it'd be called Sellworking. For the record, I believe the best thing that sells your book is your next book.
Probably best to get online. I'm a big believer in online networking, but I think my take is different than others'. I also tend to think my expectations are fairly right-on, since I've been online consistently since 2004. It's really just another way to network. I spend far more time online than I do in person networking, but for me online is a supplement to face networking. I like to see your face. You should like to see mine. (Here, let me go put my contacts in first and, like, comb my hair or something...)
Publishing is an entertainment business. This one has two parts.
a) Entertainment. That's your job. To make people laugh, cry, think, forget their lives for awhile. First and foremost a book (the fiction sort, but a lot of nonfiction too) entertains. Just like an actor or a musician entertains.
b) Business. People. Want. To. Make. Money. Off. Your. Writing. 'Nuff said.
Introvert ≠ shy. The difference between introvert and extravert is whether being around people costs or gives you energy. By that definition, I'm an introvert. Many people argue with me over that because I'm outgoing and friendly. But you can lean strongly into intro--er--version?? Introversion? (yay, it's a word!) and also be outgoing and talkative and friendly. Read this article for more information, though I don't like the start of it. I'm most definitely an introvert, though I don't ever need to be dragged to a party.
You can learn to be outgoing. Practice actually changes the chemistry in your brain. A little story: When WorldCon came to Denver, I couldn't miss the opportunity to go. Worldcon is a couple of hundred bucks to attend, and I knew by then I'd like to stay downtown in a hotel because the real action happens at the parties. Those tend to run late. So for my birthday I got 5 days in a hotel down in Denver. And since I was spending all that money I realized I'd better make damn good use of it. That meant going in there and talking to people. Writers. Editors. Agents. Who I didn't know. And damn, was I ever nobody. Gulp. Skeered, I was so skeered! But I did it. A little bit. And then I did it again a little more at the next one. And again. And again, until I hardly have to think about it any more.
Worldcon in Denver was the start of my networking career.
Networking has a slow build. And, btw, so do most careers in publishing. The shortest direct result I've seen from networking was my last book deal and it still took six months. It was a deal that also resulted in my getting representation by the fabulous Sara Megibow as well. That took... well, put it this way: I've been in Rocky Mountain Fiction Writers for seven years and meeting Sara was a direct result of my being a member of RMFW and reaching out to all my contacts therein.
Next we'll start talking the mechanics of the thing.