I'd say cigarette trousers in black or navy, and some kind of top (a shirt or jersey top, maybe a pussy tie blouse to look a bit dressier). Desigual is too patterned for my tastes, have a look at J Crew for ideas - I think preppy would work.
I'm currently LOVING the pleated skirts that are around, there's a gorgeous blush coloured one in M&S with an asymmetric hem. Sounds grim, looks stunning.
Cos is also a good place to look (don't be put off by the website or the fact you think everything will look like a sack. It won't, the cuts are amazing). It's very popular in my company (media).
I'm lucky to be able to dress down at work, so wear jeans and trainers 99% of the time.