You have to be one of the most likable people on this site! You do it by being friendly, supportive, and kind. You don't need to change *you* or become a better person, you are already a good person. Tweaking a couple of small behaviors could change other people's impressions.

It's tough to overcome the inclination to be quiet in real life. Maybe start with smiling directly at people? Toss in a compliment or a positive statement about wherever you are or the weather? The smiling and a quick 'hi' shows willingness to engage, which makes people more likely to chat, which takes the edge off feeling alone and like no one wants to talk to you...

Sometimes I decide that it's okay to just be how I am and not engage and not beat myself up for it. Being social can take up a lot of energy for introverts.