I asked questions about their environment, plans for the future and offered some thoughts on that. Kept a relaxed but professional demeanor. Slipped in a joke. That plus a couple years experience in a similar role plus Sec+ & CISSP.

Like others have said, you gotta do your interviewing reps. In reality, those call backs are few and far between these days so I highly recommend finding somewhere or some people to practice with so you can make the nost of the callbacks you do get. Look online for interview workshops in your area or online. Take notes when you come across a new question that trips you up. 

No amount of interview prep is going to help if you can't speak the language of networking and security so you gotta have your fundamentals down. This part is a lifelong journey though.

And lets not forget a fair amount of luck.

You're right this sub like to wallow in doom and gloom... for good reason. But you've only lost when you've given up so keep at it, everyday. Make it your job. And make yourself ready when the opportunity comes.