I don't believe in faking it until you make it, but I do believe in living your way towards your goal. Its no secret that your appearance matters. If your success is in the corporate arena, that means you need to look like success to reach your goals of success.
This doesn't mean you run out and get the Rolex watch, Gucci loafers or Harry Winston stud earrings and a Hermès Birkin bag; heavens no. You should, however, ensure they your shoes are in good condition (even if they are sneakers), your earrings should not be the same "fun" pair you wear on the weekends and your purse should be of good quality and give off an "I mean business" energy.
Before you open you say hello, you are being assessed by how you look. If it's a client, they see if your image is either a reflection of their own or the one they are aspiring to. If it's your boss, the question is if you represent their company. If it is your peers, then they are measuring the competition which is you.
What you may fail to realize is how your appearance has an affect on you internally. It can give you a lift to carry yourself better, feel stronger to walk into a room and own it. Externally, is affects how people interact with you as well. A well pulled together person is perceived to be successful, either in money or connections. Therefore the interaction you have with others is better just from how they perceive you.
From the moment you walk out of your house, you are on! You appearance to those around you has a weight on your success. How you are, from head to toe, gives you an energy that attracts good things which in turn helps to move you closer to your goal of success. Everything matters when success is your goal, so don't leave anything to chance.