i think ann and banana are good options. Black is a good option. A nice bag (that can hold a laptop if that is something she will need/have) can also go a long way to looking sharp. Scarves can help mix looks up if she is a scarf person. I travel with one jacket, 2 pants and a mix of tops and scarves and it lasts me a week (same for when not traveling). Shoes maybe Rothy's (also machine washable).
Here is a thread about some other options.
https://www.reddit.com/r/Lawyertalk/...ations_womens/
DS #1 Summer 05
DS #2 Summer 07