For work appropriate attire, you cannot go wrong with:

1. Neutral slacks, black, blue, tan, grey, taupe. I don't know what your body type is, but think a little bit wider leg, not too high waistband (this is dated), but you don't have to buy the ones that fall off your butt!

2. Pencil skirts for a finished look are great. If you are short, have your skirts shortened or buy them at knee length.

3. A few good jackets, preferrably not boxy styles, but styles that come in at the waist and are not too long. Only wear a long jacket if you are very tall! So, what I'm talking about is shorter hip length with a sash or detailing so that the waist is defined. You probably want these to be in neutrals if you want them to stretch into a mix and match wardrobe, but I love a jacket in a color that pops like bright blue or bright apricot. If you have neutral slacks, you can pair those with an amazing lot of things

4. Nice well fitting blouses, or tops. This is where I usually try to find a pop of color too; or even some patterns (don't go too big with the pattern unless you are a large woman, then you can get away with a bit more).

5. Accessories are your choice. Scarves are nice, long necklaces, etc that accentuate your outfit colors. They do not have to be the same colors, just look well with the colors in your outfit.

6. If you can handle it, heels help an outfit. But, just don't wear real clunky shoes and ruin your classic look!

It is my opinion that classic clothes do not go out of style. Let your personality come out in the colors you wear and the accessories you wear.

This is pretty generic, but I don't think it is a bad start. I did see that you mentioned that you bought tights?? Tights to wear under skirts or tights just to wear? Tights alone are work out clothing or casual wear and probably not appropriate work attire.