Programming on paper, do and do nots [on hold]

I am participating in our country's ICT Olympiad, and I have to code on paper. I don't know why, and I probably never will, but I have to do it. So I need some tips on the following things:

• The Olympiad will only consist of C++(or C) and HTML(CSS and Javascript included).


• The exercises aren't very hard, but every bug can cost you the exercise


• HTML is the main problem, because C++ programmes tend to be linear, while HTML require imagination.


• How can I improve my skills and debug the code?