(Throwaway account because she knows my real one)

Looking for a bit of advice. My (29F) closest friend (33F) has severe anxiety associated with public speaking. We work in the same professional field, and unfortunately, the job requires occasionally speaking at large events. This fall, she will have to give a presentation at a national meeting; it's not in question that she is prepared and will do very well, but this is the largest event she's ever spoken at and I can tell the dread is already really affecting her.

I will be accompanying her to the conference, and we're sharing a room so I'll be with her leading up to the event (unfortunately, it's on the last day, so there will be a lot of lead-up time). I know I can't do anything to take away the anxiety. She does have an appointment with a professional in the near future, so I am hopeful that will be a step in the right direction for her - but I know my own limitations, I'm not trying to "fix" anything. But she's the world to me, and I just want to do everything I can to make that time even a little more bearable.

I have relatively mild anxiety, but I have severe depression, and I know I get very frustrated at times with the things people (even well-meaning!) will say to me. One of the reasons we became so close is because she's always been amazing at supporting me and being there, so I want to return that favor. So I guess my question is, does anyone have any advice on ways I can best support her and be a good friend to her during these stressful few days?  Things to say/do (or not say/do!) leading up to a high-anxiety event? 

Thanks in advance.