It's good to have a least one or two high quality suits. They can be pantsuits or skirt suits or one of each. It would be best to get them in one of the neutral colors you have already chosen. Next is to find a few pairs of pants that can worn with a variety of tops as well as the suit jackets from your suits. A pair of rayon or wool black pants is a great item to have in your closet.
Black pants go with everything from a nice blouse to a tee shirt.
A couple of casual but fashionable pairs of pants is the next thing to focus on. You want to look for something nice enough to wear to work, but casual enough that you could wear them on the weekend. Cotton is a good fabric to look for here. A couple of skirts will round out your collection. Again, go with a neutral.