I've been dressing to make an impression for years. In school and college I used to keep a collection of clothes that would allow me to "blend" with different social groups; so you would wear black and red and steel jewellry with the goths, take off the chains and add some plaid and you'd fit in pretty well with the punks. A ratty t-shirt and some baggy t-shirt and you could hang out with the skater crowd, or a number of the just-regular-joe people. It's really not hard. I used to challenge myself to see how many groups I could 'pass' with. I think I was only ever outed a time or two.

When I started interacting with people older than my peer group (aka, the adult world) I dropped "fashion" almost altogether. If you look like you pay too much attention to your clothes, older people think you are flighty.

Plus 'being fashionable' generally does not mean you are dressing to show yourself in the best light. (as evidenced by the number of people in skinny jeans who should NOT be in skinny jeans. Before that, recall how often low-riders worked for people).

It's true that "classic" wear is harder to find; Seb gives good advice, a higher end store will stock more (the upper class is more about being chic than fashionable) but if you know what you're looking for, you can find it.

And because fashion is cyclical, if you can wait until 'your thing' comes in and buy things that are unlikely to date. Until the last year, I had a hell of a time finding pencil skirts. I wear pencil skirts (or sheaths) almost exclusively because I am very short and curvy. Any extra material, flair or flounce makes me look chubby, but a classic pencil puts curves in all the right places. So I bought three pencil skirts this year. I look best in jewel tones; red and purple and blue. They've been in in the last few years, so I've gotten several blouses and scarves. And I can't wait until kitten heels come back in... stilettoes are fine, but not as practical for everyday wear.

All three of those "trends" will last a long time; they'll never be fully out of style, as long as you wear them well. There's the odd one that will look dated; I recently retired a red satin blouse because it had puffed shoulder sleeves that dated the look, and even that would have been fine except the trend is for muted fabrics (three strikes, in other words). And it's fine to follow trends if they work for you; leggings and tunics look ok on me, as long as I'm wearing pumps.

I realize after the length of this comment it will be hard to make my case that I'm not a girly-girl. In fact, I was in my second year of college before I even knew how to apply make-up. But when I realized I would soon be consorting with a much more polished crowd, I found a boutique that offered makeup lessons and I started paying much closer attention to, as Sebastian says, making the impression I wanted to make.

I disagree, Peter. The information does not date all that quickly-- particularly mens fashions. If you bought a very classic suit ten years ago, you would be able to buy a new tie and wear it tomorrow -- no one would be the wiser.

Certain things are fadish --tie widths and shirt collars come to mind. But business styles change slowly.

I took my partner out to get him tricked out. He had a white shirt and black dress pants and a black tie when he started. We got him a black sports jacket (acceptable in all but the most formal venues) and a pair of grey pants, and a red dress shirt and a blue dress shirt, and a tie that matched all three. That is enough basics to get through a round of job interviews or a week long wedding. In, say, 5-7 years, he may want to update the jacket.

The rule of thumb is up to two neutrals and a pop of color-- any color you want, as long as it looks good on you.

Certainly, there are things that are tougher to learn; the difference between European tailoring and American; how to make sure things fit right (off the shelf dress-wear is astonishingly poor fitting). To that end, I would recommend finding some classic styles (ask the salesperson to assist you, and do a google search before-hand so you have a basic idea) and find a good tailor. Classic, well-made piece will cost about 50% more than you are used to, and tailoring will add another 20%, but you will have clothes that make you look polished and confident.

Certain fashions may go out of style, but style never goes out of fashion. There are certain universal principles that are important in developing style - having well-fitting clothes, colors that complement your skin tone and each other, layering, etc. Those elements will never go out of style. While certain specific types of style may become outdated, there are many many aspects of fashion/style that will never be obsolete.

"You won’t be perfect right away, but like any other skill, with practice you’ll rapidly improve."
"It takes very little cognitive energy to begin this process."

I disagree that it takes very little cognitive energy to begin analyzing fashion. I would guess that its actually fairly hard for your target audience to start noticing fashion details without someone continually pointing it out to them over a long period of time. Fashion can certainly be frivolous. But its a game/skill as you point out. And many people are horrifically bad at that game. So they rationalize away their incompetence by saying the game was stupid to begin with.

Another reason to study fashion is that scholarship is a virtue of rationality and if we interpret that virtue in a broad sense, it includes studying fashion. While fashion is not a scholarly discipline, there is still as large amount of information that goes into good fashion choices. Such knowledge is often related to facts about human anatomy, perception and biases. As fashion changes very quickly, much of the information is time sensitive - what is cool today is dated tomorrow. But there is still some important information, such as how to artfully conceal flaws, that is timeless.

Dress code is like A and O. It depends on where you are and what kind of people you are interacting with. I say: It´s better to look classy than sloppy...