It all depends upon the artist. "Todays hit country" is
very 80's rock informed. The country-rock acts are really not I-IV-V root-fifth material anymore. I know for a fact that a lot of the top $ acts have been vetting "rock players" and specifiacally looking for tatoos, rock-hair, etc...

It's sad, but part of the game here in the commercial music world...
a) Make sure you have the audition material memorized. Make sure all of your gear is in proper working order. Borrowing a cable, battery or tuner at the audition is a bad start! Whatever you do,
don't "noodle" between songs! That'll kill your audition every time.
b) The first gig is 80% about your musicianship and 20% about your personality. The remainder of your tenure will be 20% musicianship and 80% about your personality! For an audition, you have to nail the material
and establish a good rapport. Both of these are accomplished by
listening (more than talking or playing).
c) You cannot fake who you are. Be yourself- if your personality isn't a good fit, then the gigs not for you - and that's ok!

Everyone is miserable when a member of the team doesn't fit in.
d) Don't mention you're a "Jersey boy". Trust me, as a native NY'er, moving to Nashville and re-establishing a career was a lot less challenging when I embraced the culture shift. Of course, the country world is full of transplants, so if the artist sounds like she's from Jersey, you might have an "in"!
e) 5 strings are undeniably more common in the current modern-country studio scene. However, current trends are pushing more for 4-stringers in touring bands. (stupid "rock" stereotype imaging again...) I'm preparing right now for a 3-artist package tour. While there is a lot of 5 string work on the records, I'm still preparing the material on a 4 string as I know the artists & some of them go more for the "old-school" approach. At the same time, if the decide they want a 5er, it's no problem. I always carry both... Ultimately though- you need to play what
you're most comfortable with!
f) Smile & be positive! A positive & energetic attitude go a loooong way in establishing a good 1st impression.
g) Female artists need a little more care. (I assume you are a male) Be sure to be gentle, respectful, and shake the boyfriend or husbands hand.
just my opinions, but I do make a living doing this sort of thing. YMMMV....