Just don´t try to hard to think about the situation, when you´re in. Staying calm might help, but in your case you must be trying too hard to think about not turning red. Do it like other men, just ignore what she´s saying (not completly though) and think about other things, like what you´re going to eat or naked teachers or something like that. xd
When you do feel that she´s in to you, you should just ask her out for a date maybe.
You get to know her much better, and get used to being around her.
-Avoid starring at her while talking
-Think about other things while she´s talking
-Try to get on a date with her to get used to the situation
Did she ever noticed something, or even said something about your burning face?