I've been developing for about 4 years now, 'seriously' building fairly complex web and mobile apps for about 2. Yet, every day I run across articles here and comments that make me feel incredibly useless and inexperienced.
How do I bridge that gap between where I am now, and being able to spend time browsing through modern php, ios, (whatever language I know) articles and not feel under water and under the average knowledge bar?
I still run across stuff I don't understand, all the time.
And I'm not one of those people who have "1 year of experience 15 times" instead of "15 years of experience". I'm pretty aggressive about learning new stuff and expanding my horizons. And yet the pace of change is so fast, there's always new stuff coming out, or areas of tech I'm discovering for the first time.
The moral of this little diatribe? Don't sweat it. Be curious, explore, learn, hack, and don't worry too much about comparing yourself to others. And don't assume everybody on HN is some uber-genius, super-brilliant "10x" programmer. I mean, sure, there probably are people like that here, but I'm pretty sure they are a small minority.
For another take, you might find esr's "How to become a hacker" essay useful:
http://www.catb.org/esr/faqs/hacker-howto.html
Other than that, my only advice would be to start a project (open-source or not, whatever you think) that gives you a venue to challenge yourself. That is, start a project that you don't believe you're really competent to complete, and then go do it.
Also, "read a lot".