You only get one first impression so it has to be a great one. Since you never know who is looking or when you will bump into someone important, you must always go out wearing something that makes you look great. You are also building a reputation of someone who looks good. People tend to subconsciously act like they feel like they look.
Go through your wardrobe and throw out everything you wear that doesn't make you look like a million bucks. Yes, this is very hard to do because you are attached to those old clothes. If you have not worn it for over a year, throw it out. Warning: you might not even realize how nerdy some of those things make you look so this is a good time to bring in a good friend that is able to be honest with you.
Once you are done throwing things out, go out shopping somewhere expensive where the clerks will help you find some clothes that look awesome. You don't need tons. Ideally you should end up with around 5 complete outfits from head to toe that fit your look and build perfectly. Then you can stop stressing about what to wear and rotate through your options.
To keep things fresh, you should consider using a service that sends you things you might look great in: Trunkclub.com OutfitEZ.com Bombfell.com By completing this goal you commit to looking your best at all times to build your reputation and being ready for the most important first impression of your life.