My VI was on 10th of Jul 2012. 7:45 AM slot. My Token number was 368, so I had enough time to observe how other VIs were going on.
The rejection rate on that day could be around 50% to 60% but most of the rejections were very obvious. I could see that most of the people with good confidence and clear intentions (as I heard in there answers) were getting visa approved. And then my Token flashed on the counter number 26.

He was a American guy in his early 30s. I was observing him, he was doing his job very carefully and the rejections he did were quite obvious. There was no one when I went to the counter.
I had a big smile when I approached him and passed him passport and i20 before he asked me to.

Me : Good Morning !!
VO : Good Morning, Long Beach huh (seeing my i20)

VO : Why Masters?
Me : I did my undergrad. in IT which was less technical and during 4 years of my profession life I have realized that I was missing technical skills which I observed in my seniors at work and thought Masters could be a chance to learn more about computers and posses such technical skills. (he seemed to be convinced with my answer)

VO : Which colleges did you apply to?
Me : CSULB, UD, SDSU and SJSU (Full forms)

VO : 4 Year !! Where did you work and what was the work?
Me : I have worked at BMC Software for 3.8 yrs and since last dec I am working with Cognizant. I was product developer in both the companies.

VO : Coding? (with gesture of typing on keyboard)
Me : (With smile) Yes, Coding (with gesture of typing on keyboard)

VO : Who is funding you Education?
Me : I have my savings and my father has his savings which I will be using for my education, My father is Teacher.

VO : Ok, I am approving your Visa, It will be delivered to you in 2-3 days.
Me : (I was so surprised and couldn't believe what what I heard, so just to reconfirm I asked him) Is my visa approved sir?
VO : Yes (with a big Smile)
Me : Thank you sir !! You made my day.. (I was feeling so grateful to him; I wanted to keep on saying thank you.... )

Yes... with these very few questions asked and no document checked my visa was approved. Perhaps luckiest day in my life.

TIPS :
- Keep answers "short and sweet"
- Try to be confident and speak with clear pronunciations.
- Smile adds some charm and makes conversation pleasant.
- If you could try to be little funny (without overstepping the seriousness of the process) it can help, hopefully this would humor the VO.

All the best for your VI !!

Regards,
Roshan