One of the most powerful and impactful bits of career advice that I have ever received is the practice of treating every day at work as a job interview.

Whether you like it or not, you are constantly being evaluated and re-evaluated by everyone around you. How you dress at work sends a number of signals about how you view the environment, how much respect you have for your work and yourself, what groups you identify with, and where you think you belong. So if you dress more like the peer group you aspire to, and less like the one you are in, you are sending a powerful signal that you belong in that group.

In addition, there is a common perception among management that if you can't handle the small things, you probably aren't well suited to handle larger responsibility. Put simply: If you can't even dress yourself properly, you can't handle much else.

I saw this on a daily basis at several Fortune 500 firms while working as a consultant. Early in my career I dressed like all the other IT guys did: khakis and a polo shirt. Then I met a senior consultant that became my mentor who insisted that I ditch the polo shirts, and start dressing a little more like the managers and the people in the jobs I aspired to. Just a simple change to nicer slacks, more formal shoes, and wearing button down long sleeve dress shirts made a huge difference in how people viewed and treated me. Within a few months, I was rapidly promoted into areas of increasing responsibility.

Years later I worked for another consulting firm that had a simple policy that we were to follow the dress code of the senior leadership (the CIO and his team), not the engineers. So we often wore dress shirts and ties to work. Working side by side with us was another highly paid consultant who worked directly for a major software vendor. He was the actual subject matter expert for the technology that was being deployed, and his hourly billing rate was significantly higher than ours. However, he always came to work each day in a vendor polo shirt, jeans, and tennis shoes. He even asked me once "So how come you guys are always dressed up? Why are you wearing ties?" I explained our policy, he scoffed and said proudly "I'm an engineer, I don't want anybody to thing I'm anything else." Well, he was right - nobody did.

During the project a number of issues arose and each and every time the CIO would walk right past this guy and come to us for advice - over and over again. Even in meetings where we were all at the same table, his opinions seem to carry less weight with the client's management and the key decision makers. In many of these meetings he was the only person in the meetings wearing a polo shirt and he still didn't get the hint. He was signaling that he didn't belong at the decision makers table. When issues arose, his explanations carried little weight. He lost credibility with every meeting. Needless to say, that vendor wasn't on the project for long.

I work with senior Fortune 500 executives every day. The days of wearing suits and ties to work are largely reserved for the banking and legal industries, but there is still a level of professionalism that is expected at nearly every firm. (Note: I realize Silicon Valley culture is a lot more relaxed and casual, and it's common for CEOs to wear t-shirts and shorts. But outside of the tech reality bubble, how you dress matters in most professional work environments.)

Regardless of the level of the organization I'm engaged with, I always take my cues from the senior management. Slacks and a button down shirt are my standard dress, as is typical in the executive ranks today. If the customer has a casual day on Friday, I'll wear a dress shirt and jeans. On a hot day, I might wear dress slacks with a polo. But never, ever jeans and a polo. At after work events, I still strive to be the best dressed within the expectations for the occasion. Clean shoes, never have a tie half undone (you look like you're drunk), always pressed shirt. Never be the first one to roll up your sleeves. If you take your appearance seriously, people will take you seriously (provided your behavior matches).

Again, treat every day like an interview and pay attention to what it's like to meet you. You don't have to out dress everyone else, but you should be well dressed for the circumstance with respect to the corporate culture.

Or as my mentor would say "Dress like the organ grinder, not the monkey."