I guess one of my problems is that I don't spend enough time preparing my solution on the paper. Specially thinking about edge cases ... So I really need to submit the code and find out about some special cases that can break the program.
But going into details means thinking more at the beginning. I am not sure how much thinking on paper is enough in a technical interview. (considering I know about common data structures and algorithms)
On average how much of the actual coding part of the interview is ok, to be just thinking on the paper? 10 minutes? more? less?

Thanks :)