I was rejected twice in my F1 Visa interview. My Experience:
I was rejected in my first interview because I gave more of a ambiguous answers( I was rejected because VO did not see my Intents of being a student and intents of returning home) and I was more prepared for my second Interview. The Second interview went like this:
Me:Good Morning Sir.
VO: Good Morning, You were given yellow slip before. Why were you rejected by my colleague?
Me: Sir, Basically I did not clearly explain my intentions before. So I think that was the cause.
VO: Ok, What did you do after your under graduation?
Me: I worked in a local xyz consultancy firm.
VO: How long?
Me: For about 1 year and 2-3 months.
VO: Why Environmental Engineering?
Me: Well, I want to do my Masters in Environmental Engineering with the specialization in E3(Energy, Environmental Economics). (And I was just getting started with the scope of Hydropower, my choice and applicability of my specialization in hydropower, I was interrupted and was asked next question)
VO: What do you want to do after your graduation?
Me: Sir, I want to work as a consultant engineer in a hydropower company here in my country (In my First Interview, I was basically taliking about my long term goal to work in the planning commission in the government as a policy maker). (But before I could explain that was my short term goal and I want to work my way through in the planning commission, I was asked another question)
VO: Wow, Your University is Expensive? How will you afford that?
Me: Well, My parents are my sponsers. They work in xyz company. My father is an Engineer and he is working as a deputy manager in xyz office and my mother is yz. They have a combined annual income of about 22000$. My father has a savings of about 58000$ which will suffice for my first year costs(which is around 46000$/year) And for my second year, my parents have funds in Provident Fund, Citizen Investment Trust, shares which in total is about 68000$ which is sufficient for my second year as well. Also we have lands and houses in cities as a back up.
VO: I am sorry, I find the similar reasons as my collegue. I cannot give you a visa.( This time, it was my Intents of returning home and the issues of fundings as indicated in the yellow slip)

Few things I missed to say in this interview:
I am the only child. It is my responsibility to look after my parents and my privilege to work and live with my family here in my country. My responsibility as a only child to look after my assets. I want to specifically work in designing the Energy plants and Transmission lines to meet the sustainable and environmental goals, Financial and Market analysis of Energy demands, Design of Tariffs and Service costs to sell the energy generated to local and international market and so on as a consultant engineer.

I am planning for the third interview(btw the final one) for the next term, as the arrival for this term is soon and I will not find the dates in time. I will apply again for next term. Should I take the fixed assets and make it a liquid asset so that I can show that I have liquid assets for a full course of study? Any suggestions? How should I make my case strong?