First of all, thank you all for your answers! It's incredibly instructive to get so many helpful tips.
rachylou, tulle, I definitely need more brooches. Thank you tulle for all your ideas!
jussie, L'Abeille, thank you for the scarf tips! I love small silk square and tieing one to the bag handle would look lovely.
Thank you for your ideas The Cat, larger earrings would be great!
La Belle Demimondaine, thank you so much for your detailed ideas! I love the idea of layered necklaces.
lisa p, Brooklyn, Isabel, and again La Belle Demimondaine, I think you raise an interesting point with hairstyle and makeup. I'm indeed used to wearing minimal makeup and styling my hair in a tight high ponytail or braid for work, and a more elaborate makeup and hairstyle could help adding pizzazz. I'm currently very bad at styling my (long and unruly) hair, but that's definitely something I should learn to do. Same thing with the makeup. Thank you very much for making me realise that!
shevia, yes, attitude also greatly impacts the actual rendering of an outfit...I always feel awkward when being photographed, which does not help soften my looks on the photos!
Torontogirl, Amy Isabella, Cee, thank you very much for your inspiring words!
Jane, Sal, thank you! I will have to try to use the white bag and the scarf for similar looks.