well what i consider as important to keep in mind are;

first you should be confident of what you are expressing there
second you should not be judgemental in any case rather say "this is what i think........
thirdly, see the interest of your country and alway defend that...........critique rather than criticism.
fourthly, if you disagree anything do it but in an agreeable manner.
fifth, if you don't have any answer don't go for guesses, say sorry i don't have any concrete information about that..
and lastly, how you present your opinions, ideas and all of your stuff is very important.......done

Do you agree