Holy mackerel, how long are you going to be there?
I thought
I was an overpacker!
If it were me, I'd pick one or two "theme colors" that can go together for accessories (scarves, jewelry, belts, hair toys) and then some neutral stuff (e.g., pair of jeans, skirt, black dress, button down shirt, cardigan, t-shirts, one pair each heels, flats, boots). After struggling around Europe with unweildy and heavy suitcases one too many times, I am finally converted to the packing lighter or "capsule wardrobe" approach. You can wear the same black dress to any number of events, with a different pashmina/earrings/hairdo/tights/shoes and nobody will notice that it's the same dress. A nice cardigan or sweater can be casual or dressy depending on whether you wear it with jeans and flats or a skirt and boots. Likewise nobody will notice or care if you wear the same shoes every day, or wear your jeans over and over (unless they get dirty, of course!). Have a look at
http://www.academichic.com/category/wardrobe-challenge/ for some examples of wardrobe remixing.
Accessories are a lot lighter and easier to pack than a series of whole different outfits, and they can be cheap to buy as souvenirs. The same with toiletries--I'd just bring a couple of days' worth of stuff in your carry-on, and buy more when you get here. It will be less of a struggle in the airport.
I don't always practice what I preach, of course, but I am getting better at it. DH and I went on a two-week trek through Scandinavia earlier this summer, with only a small-ish backpack each, and it was so much less stressful than having a big suitcase to deal with. We took twice as much on a short trip to his parents' house a few years ago, and the stress of hauling that big heavy suitcase through the London underground to change trains just about ruined the trip.
