I love black and feel great in it, and I don't feel the need to break into colour too often. I find looking at other people in colourful clothes is enough for me. It doesn't mean I don't love colour, just that most of them don't look great on me. Black is not supposed to be my best colour, but I bend the rules just enough to make it part of my palette!
It is also a very easy colour (or non-colour) to build up a capsule wardrobe with - everything will match and all the neutrals will blend in so easily! Black skinnies, black leather leggings, black blazer, black trainers, black boots, leopard ballerinas, white shirt, beige jumper, black jumper...you get my drift? As long as you know how to combine it with the correct tones for your colouring, I say everybody can wear black. I believe the same goes for any colour - there is usually a shade of any colour which will flatter you most, and it is really only the items which are directly near your face which really need to be "right".
I am not a strict follower of colour "rules", but the basis for them is a good place to start so you can always choose the most flattering shades (read between the lines as - help fade wrinkles, bags under your eyes etc!). A quick fix is to determine which metal is your most flattering. If you look better in silver, you are most probably suited to cooler colours or the bluer shades of colours. Your hair is probably blonde or lighter brown and your eyes blue. If you look better in gold, then chances are you are warm-toned with a peachy complexion and have darker hair (or red) and green or brown eyes. You will look best in colours which have warmer orangey undertones. Often you can tell by the colour of the veins in your wrists - blue veins=cool, green veins=warm.
So these rules are all very well, but I am guessing we really just want it cut down to how we can still wear our old favourites? Black, white, grey, khaki, beige, camel, blue...
Black is only your best friend if you have strong, clear features. The one forgiving thing about black though, is that it is so striking, the eye is drawn into the colour itself and not so much the face! Black can look just as good on pale ivory skin as it can on deep olive skin - it is the clarity of the skin which makes it "work". If your skin and overall look is more muted, add a layer underneath your black in a tone which is more flattering (e.g. cream for warmer autumns or springs and white or pastel for summers and winters) or lots of jewellery in your tone of silver or gold. Another alternative is to up your make-up, especially your lipstick!
For wearing white, you are good to go if you are cooler toned (the ones who look better in silver). But make your white verge into creamy tones, if you are warm. Grey is much better suited to the cooler people too, but the shades merging into beige) are better for the warms. The yellow toned beiges, camels, and browns are for warmer toned people and the silvery greys, and taupe beiges for the cool toned. Khaki is for the warm, but wear it with other colours close to your face and you are fine. Blue is a cool toned person's best friend, it will do absolute wonders for your skin - inky, midnight blue is always going to be more flattering than black for you. But the yellow shades of blue like turquoise and teal are great on a warm skinned person.
The diagram below is one of the most simplified versions I have come across for defining your colour palette. (I believe you should go with whatever your current hair colour is- dyed or natural).
So get out there and wear your best colours - just make sure you are All Black for the rugby on Saturday?!