[Interviews] Got a 2nd interview for a job I really want. How can I not let my eagerness and nerves mess me up?

I've been looking to transition out of contract work and into a full time salaried position. I found a position that fit my experience almost perfectly, is in a good industry for my skill set, has room for growth, and has almost everything I'd want in a salary/benefits package. If you'd sat me down and asked me to write out my dream job, this is almost the exact job I'd come up with.

I had a phone interview on Thursday and they contacted me soon after to set up an in person interview for later this week. I'm prone to anxiety (I actually had a small panic attack during an interview once) and can babble/forget things when nervous. It's been awhile since I interviewed for a position I was actually excited about and I'm worried that I might mess myself up.

What can I do to not appear over-eager, help calm myself down before hand, and just generally avoid being my own worst enemy?

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official