You sign up to a forum with geek in the name, buy stickers and T-shirts with the word geek on them, stick the stickers on your favorite things that you bring everywhere, wear the geek shirts out in public and explain what geekhack actually is when people inevitably ask you and then proceed to explain that it's not just regular rubber dome keyboards you like and then explain what a rubber dome keyboard is when they inevitably ask and when they finally stop asking questions, you continue to explaining mechanical keyboards and switches because you can't help yourself and then realize that these people really don't care but you continue because just stopping abruptly would be awkward and the last thing you want to do is come off as both a geek and awkward.