There are two broad themes that have surfaced in all these interactions.
One is the ever present communication skills.
It's not just how you say it, it's knowing what is asked and how to
The essence of communication is to understand the other person and
making him understand what you know.
The second thing is don't just use a programming language or tool,
Most of the people who came for the interview just knew how to use the
tool. When asked why they were using such and such feature, they
Asked about a programming feature, they stayed mum. They have used it
but don't know it's purpose.
Each of them was clearly using the language or the tool but when we
digged on why such and such analysis were carried out, most failed.
The lesson don't just use it. Learn it!!
More on skills development can be found here http://my-aesi.blogspot.com/search?q=skills