Don't be discouraged if no definite offer is made or specific salary discussed. The interviewer will probably want to communicate with the office first, or interview other applicants, before making a decision.
Make sure you answer the following two questions: "Why are you interested in the company?" and "What can you offer?"
Ask for the interview's business card so you can write a thank you letter.
Follow up can be crucial. After your interview, immediately write down key issues uncovered in the interview. Call your recruiter if you think you'd like to discuss the same. Call your recruiter if you do not hear from them in the specified time period. A thank you letter should be written if a job offer is made.