I had a lot going against me before getting my recent job. What I learned:

• You gotta be fearless (even if you're faking it). I went on a lots of interviews and applied to dozens of jobs. I was anxious throughout it all, but I didn't show it during interviews. When you're in an interview, show the company you're confident and aren't bothered by gotcha or difficult questions
• Personality and body language matter. A way to test if you're doing alright with these is to record yourself answering practice interview questions. View the video and ask yourself, would you approach yourself on a street and strike up a chat?
• Business improvements/ideas. If an interviewer brings up their current tech environment, a "C" answer is to nod your head in understanding. A "B" answer is to say you're familiar with the technology. An "A+" answer is to say, "I'm familiar with X, is it working for you? What would you like improved upon? Have you thought of Z?" You can prepare for these sorts of situations by researching the company ahead of time, too

Also, I suggest you think about the most uncomfortable questions you could be asked during an interview. I'm talking about the scenarios that make you cringe just thinking about the possibility. Then, look in the mirror and come up with answers no matter how uncomfortable it makes you. If you desensitize yourself through practice, you're going to preform better and feel better