I think it would help to make a distinction between "classic" and "basic." Both are good, but the two aren't exactly interchangeable. Through uni I did design work, and also worked in retail dressing all kinds of women. Bear in mind that I'm American, I've kind of worked out since moving here that aussie dressing norms are a bit more- relaxed- than what I've been used to. So if I come off a little "snobby" (Dh's adjective for how I dress), I'm not. Its just difference.

"Classic" conjures clothes with a certain sort of style to them- clean tailored lines, tasteful but interesting designs, pure colors, clean patterns.
"Basic" would be more of solid colors (think navy, black, white, "safe" colors), durable pieces, interchangeability, and, well, basic designs.

For example- T-shirts are a basic. Knits have little to no place in a classic wardrobe. There's just something, well, basic about them. I'm not knocking t-shirts, I love them. Classics are more of woven fabrics, good cuts and drape, carefully selected to fit well. There's a certain amount of overlap between the two categories I think, but not much really.

An absolute 100% must for a classic wardrobe is a little black dress. It's hard to tell you what kind to buy, since I don't know your body shape. Do a bit of research (or you may already know what best flatters your figure) and buy a dress recommended to suit your body shape. Don't buy one that's too small. It will look awful. And you'll see a pic of yourself in it and feel awful and never wear it again. A good little black dress is versatile- good for parties (with pretty stockings, good makeup, killer heels, and a nice handbag) or for work (a cardigan, flats, shoulder bag) or for just about anything. The point is, it can be a sort of "last resort" dress that you wear when you don't know what else would be suitable/ are completely uninspired but still want to look nice.

Also incredibly important- get fitted for a bra by someone who does it every day. The ladies at Myer are quite nice, in my experience. I can't stress this enough. You'll feel good, your posture will be better, you'll look great.

Another rec- if you're going to go for Classic sorts of clothes, a good rule of thumb is to buy natural fibers. They breathe better and are more comfortable to wear. They look better. Usually more a pain to take care of, and generally more expensive- but I would soooo rather spend the same amount of money to have one well-made wool jumper than five or six acrylic ones. It just looks better. More "together."

On colors- you don't need to be afraid of color. Think about colors you've worn in the past and been complimented on. For me, that's pale greens and purples, for example. I would suggest buying a few pieces in those colors. If there's a color you absolutely adore but makes your skin look somewhat jaundiced, thats ok too. You can still wear it, just don't wear it close to your face. For instance, I have a watermelon colored swirly skirt I wear all the time and I love. But that color makes me look ill, so its a skirt. And it works.

I think what's most important, though, is to buy things that make you feel good about yourself, that you like to see yourself in, and that you are comfortable wearing. If any of those things are lacking, you'll just spend money and not wear it. And be confident. Attitude is half the battle.