Honestly the thing that jumped out at me, and it's minor, was about how her face turns red when she cries and that makes her more self conscious. A cold, wet washrag can work wonders on that. If she's already shy and having a rough day, knowing that everyone can tell she's been crying - and will probably give her unwanted attention asking about it, can be HUGE at that age and just keeps the spiral going and makes a rough situation a lot worse. To us it's a little thing, but I'd definitely use the washcloth trick on mornings like this. It's a small thing that can help turn her back to a more positive state if that makes any sense?
I agree with helping her find her own solutions. At 7 years old she's old enough to understand more advanced concepts (than say at 4 yrs old) and personally I'd sit down and just tell her that you were cautious at her age like she is so you know exactly how she feels. Tell her straight out that you always have her back, but don't always know what she wants you to do to help her and see what she says.
We have a 7 yr old DS who is a lot like your DD and he was invited to a movie party last weekend. He's never been at a "strangers" house without me or DH there and we had some tears, a lot of waffling of if we would go, etc. I just told him that I had always been like that too, and that looking back I feel like I missed a lot by not giving it a try and I didn't want him to feel that way when he was old like me. He may not have grasped all the nuances of it, but he could get where I was coming from. In the end he went and had a complete BLAST, and we later talked a little about how it had definitely been worth it to overcome his fears and take a chance and go. I try to look very hard for instances like that for him where he can have success after success when he overcomes his shyness, and always mention just a quick word about how I'm glad he had a good time and didn't that turn out not to be so scary after all (and then drop it). I started this when he was 3 and his nature was becoming obvious, and between that and just growing up, I'm really seeing differences, though it's baby steps all the way! Oh and I never use the word "shy" in front of DS. I always use "cautious" because I think being labelled "shy" has connotations of something being wrong with a person, whereas "cautious" is not necessarily considered a bad thing, kwim?