I am a professional myself

. Although I do work in a conservative and male-dominated organization, I actually don't worry much about what to wear (partially because my place is somewhat flexible, but also because I kind of ignore the workplace status quo and dress to please myself)....though I hope I can help anyway.
I think what a lot of women on tfs do is use well-tailored basics like blazers, pencil skirts, trousers & boots to tone down fun stuff like standout blouses, bright prints, unusual jewelery and funky shoes.
My normal work outfit consists of a bold top (sparkles, stripes, bright colors, ruffles, bows, metallics, deconstructed, etc.), a fitted cardigan or blazer, and skinny jeans. I either wear classic ballet flats or really funky/bright pumps. Another possibility is to wear a feminine skirt (like a floral circle skirt) with a blazer and a basic blouse underneath. I don't do this much myself, but I think it works very well.
I also like to have an distinctive haircut, so that even when I'm wearing a suit or something "proper" for important days, I feel like I am still expressing myself visually. This is just my personal taste, but I actually like the almost violent clash of masculinity and feminity from the austerity of a suit on a sexy and confident woman.
Depending on how formal your workplace is, you can vary the degree of how adventurous you are. The more flexible your workplace is, the more "fun" pieces you can get away with on any given outfit.
Lucky magazine would probably be a good resource for your dilemma.
The key thing is to mix it up! I think that's the mantra of many a tfs-er. As far as clothes go, if you have excellent fitting professional basics, you might even be able to get away with some of your going out/party pieces.

The "mix it up" philosophy ALSO applies to your attitude and how you carry out your work. If you strut your stuff with confidence and give your best effort on the job....you will sparkle from the inside out, no matter what you are wearing!
I will look for pics to post. Hope this helps!
(BTW, I think there is a thread for this topic already...you may want to do some digging around

.)