There are numerous studies that prove clothing can help a child have confidence and perform better in school. After the evidence had been gathered, many schools adopted a policy of school uniforms. I've seen firsthand how clothing can elevate the confidence of a child.
My wife and I sponsor children through a sponsorship network called Latin America Childcare. They provide education, a uniform, meals, and, at times, healthcare to impoverished children in over 20 countries throughout Latin America. I've been there when children were given uniforms—their eyes light up with excitement and pride.
It will be no different for your child. Having your son dress appropriately for each occasion will elevate his confidence and give him a sense of self-respect.
Teaching your son to dress appropriately will help him excel in life
Some mothers stumble on the idea that we should put such attention on clothing, citing the scriptural mantra: "Men look on the outward appearance, but God examines the heart (1 Samuel 16:7)." While that is very true, it doesn't exclude the fact that men look on the outward appearance. We may not like it, but it is true, there is a lot of determination about a person by the way they dress. As a matter of fact, it takes milliseconds to make a first impression.
Ask yourself these questions when directing your son in his clothing selections
Is this appropriate for the occasion?
Will this attire draw attention by overdressing or by underdressing? (Steer clear of either.)
How does he feel about himself in these clothes? Does he look confident or uncomfortable?
Is this an appropriate "uniform" for the event, sport or activity?
Is his outfit considered in style?
Cost of clothing
Don't worry; it doesn't have to cost you a small fortune to dress your son fashionably. Help him choose a few staple items that fit him well: jeans, white t-shirts, button down shirts, a pair of casual pants, a nice belt and shoes. Then, allow him to express his personality in inexpensive seasonal styles, like hats and graphic t-shirts (stores like H&M are a great option for these items).
Teach your son if a staple item doesn't fit properly, you can simply take it to a tailor. Plan ahead for big purchases, like your son's first suit.
Follow along with men's fashion
Know what is in style for your son and what will make him feel the most comfortable around his friends.
However, I recommend you do not allow your son to develop extremes in his clothes. A lot of boys adopt clothing that becomes a statement of rebellion or identifies them to a set of "beliefs" that are attached to music. If this is the case for your son, I would work very hard to distance him from those extremes.
Remember: the goal is to give your son the confidence he needs in his appearance, so he can focus on developing the skills he needs in life.