Dressing well and dressing up are two different things, often two very different things. To understand dressing up, read my description of the degrees of formality. Dressing well is a more comprehensive task that subsumes achieving proper formality as just one of its aspects. There is far more to dressing well than simply putting on a coat and tie, and it is possible and desirable at any level of formality. I see dressing well as based on seven practices:1. Quality over quantity. Real style costs more money than most men are comfortable spending. Garments made cheaply from inferior materials can be sold for less. High quality items of superior materials and construction must be sold for more. There is no way around these simple economic facts, other than the relief that comes from smart use of sales, thrifting and other techniques. On the other hand, higher cost does not always equal higher quality. Some big names charge more simply for their label without providing better quality. In fact, some charge as much or more for off-the-rack items as bespoke alternatives would cost. I do not care how much you paid, if it was not made for your measurements, it will never fit like a garment that was! You are aiming for quality not cost. Just be ready for the price of that quality.
2. Buy consciously. Become fully conscious of which garments you already own and which you need to expand your options. Learn to think in terms of an entire wardrobe that efficiently and comprehensively allows you to dress for every occasion of your life. Focus on buying garments that you can pair with as many options as possible rather than a garment that really only works in a specific outfit. Shop intelligently for the items that create a full wardrobe rather than simply buying single things that look cool on their own but do not really combine well with most of what you actually own.
3. Master fit. Perhaps this should be number one as it is the most important principle for any man wanting to dress well.
Fit is always affected by trends and fads, as one of the easiest way to spur a new fad - and spur new sales - is by tinkering with the silhouette of a garment. The trendy fit right now is rather tight and form-fitting. It was not before and it soon will not be again. You need to decide how closely you follow trends. Do you want to project more of a steady reliability or more of a cutting-edge sense of where things are going? You can, of course, choose to do both, each for the right occasion.
Instead of just grabbing the same size you have always bought and throwing it on, open your eyes to how you look and to how each article of clothing looks on you. Make use of dressing room mirrors and carefully assess what your body really looks like, how different sizes and fits look on your actual body (not on mannequins or on models in photos). Give yourself more time to shop than ever before and give yourself permission to enjoy it. Learning to take a deep breath and actually go into the dressing room and spend some time examining potential purchases in the mirror might be one of the most crucial steps a man can make towards dressing better.
The best hotels and men's boutiques in your area may make the best recommendations for a good tailor, though a good tailor is actually hard to find outside of the few largest American cities, and many men simply have to put up with the best they can find in their area. Take the time to try out all of the most highly recommended tailors in your area and identify the best you can.
Any decent tailor can hem your pants for you. Most should be able to adjust the length of your jacket sleeves. Finding one who can expertly make more complicated alterations on a sports or suit coat, however - like bringing in the waist, eliminating collar gap, rotating the sleeves, etc. - may be trickier.
As some tailors will probably screw things up due to incompetence, so will you due to the fact that you are still figuring out what you want and how to get it. This is a process of growth and learning and is part of the expense of becoming a better dresser. Take your time and be patient with yourself. It really will pay off in the long run.
Once you know who your tailor is and how much certain alterations cost, always factor those alterations into the price of a garment when you are shopping and making purchase decisions. The real price of any clothing item is: clothing item + cost of tailoring.
5. Identify your colors. Pay attention to which colors complement your own natural colors - your skin, hair, eyes - best. Every person has their own palette of colors that make them look great. When you are first starting to consider color, it might help to think in terms of two levels: base colors and bolds.
Your first step is to identify the base colors that always look good on you. You can wear these with almost any other color. If you can wear khaki chinos with any color of shirt, khaki is a base color for you. If another color for pants, say red, is uncomfortable for you to wear with most other colors, it is not a base for you. Khaki, blue denim, and grey are generally base colors for bottoms for most men. Your base colors will form the foundation of your wardrobe and should dominate it in the early stages of assembling it.
Also identify the bold colors that look good on you when grounded in an ensemble of base colors. Maybe yellow pants are a bad idea for you, but a yellow polo looks great on you with jeans or khaki chinos. Then yellows (or certain kinds of yellow) are good bold colors for you. You should branch out more into these colors once you have a good foundation of base-colored items. While you are still learning your style, only wear one bold item at a time, with everything else in the outfit a base color.
This is not scientific, of course. Some people have a much bolder palette than others who have the same hair, skin and eye colors. This is about what you feel comfortable and confident wearing. If a color makes you uncomfortable, you will be less confident while wearing it. You may find, as most men do, that the longer you dress consciously, the more comfortable you become with color and the larger your palette becomes. Always wear whatever gives you the most confidence.
It is best to avoid patterns for a while as you are learning to dress. Once you begin to master your colors and combinations with solid garments, start moving into conservative patterns. It is always a good idea to start conservatively.
While visiting the sites linked here, watching the films listed, and considering other sources of inspiration, take the time to stop and ask yourself why you like certain looks. What message does an outfit send about its wearer? What are each of the colors, the patterns, the textures, the materials? What does each say? What does their combination and juxtaposition say? What is the effect of strong contrast? Of minimal contrast? Other details like cut and fit? A more formal item paired with a more casual item? Use images of others to learn to understand how details and their combination and juxtaposition forge an image for their wearer. Master the details that express the messages you send to others about yourself.
When you do all of these things well: buy quality items that fulfill intelligent roles in your wardrobe, assure that your fit is perfect through conscious shopping and good tailoring, produce a harmonious and beautiful combination of colors, textures, and other details, and perfectly match your ensemble to occasion, you are dressing well. Again, this is entirely different from simply dressing up and can and should be done at any level of formality. The way you as an individual develop these skills is what produces your personal style.