Note: This is all just from personal experience in interviews. I'm not an interviewer, I'm an interviewee.
The fact you have an interview in the first place is a good sign - your résumé showed that you have the skills they need. A lot of the time, an interview is used to determine if you're a good fit socially. As for whiteboard coding, it's just used to show your thinking. Even if you screw it up, as long as you can explain what your thought process was they won't mind.
Anyways, I find the best thing you can do is research the company, come up with a few good questions, and tell the interviewer how it would be great to work with them. If they hit you with a curveball during the interview code test, you probably wouldn't want to work there anyways.
The fact you have an interview in the first place is a good sign - your résumé showed that you have the skills they need. A lot of the time, an interview is used to determine if you're a good fit socially. As for whiteboard coding, it's just used to show your thinking. Even if you screw it up, as long as you can explain what your thought process was they won't mind.
Anyways, I find the best thing you can do is research the company, come up with a few good questions, and tell the interviewer how it would be great to work with them. If they hit you with a curveball during the interview code test, you probably wouldn't want to work there anyways.