some my feelings/experiences:
1) If you can find out the job, apply directly or via their corporate
recruiting staff. Because they have to pay for EXTRA fees to the headhunter
to hire you, generally a couple thousand bucks.... so the interviewers has
MUCH higher expectation for you (for that extra $ reasons), which makes the
interviewing more demanding and harder.
2) Keep conversation - keep talking, they just want to hear and get more
information from you. The principle is not to let the conversation stop or
stay. If you stop talking, he/she has no other choice - but keep asking you
a lots of questions (most that you may not be good at... or unfamiliar) to
keep conversations. If so, you are on a hot table..
3) Ask one or two life questions - weather, life, etc. in that area. That
may help keep a good conversations. Ask the job duty and what they expect
from you..
Hope helps, but not necessary apply to all situations/background/jobs, etc.