Be YourselfThe very first and simplest thing that you can and should always do is be yourself. Dress like you normally dress. If you're going into an environment that's filled with tattooed skaters, don't try to emulate that. The worst thing you can do is commit to being something you're not on your first day at work. Wear the clothes that make you who you are but try to add a tiny bit of work-place flair to it. Keeping with the tattoo concept for a moment - If you normally wear a full suit, tie and shiny shoe getup then consider dropping the tie and shiny shoes in place of a t-shirt and some of your favourite kicks. Keep the suit, drop the stuffy. Always bear in mind that they hired you for who you are and not who they wanted you to be in their office environment. If you aren't comfortable from the get-go, then chances are you'll struggle to adapt.
Do You ResearchDon't go in blind. For all things good and stylish in the world just ask around. It's OK to call up your colleagues or boss and find out what the dress code is and then interpret it for yourself. Taking a guess is going to place you in a potential awkward (possibly hilarious) situation if you pitch up in shorts and slops when the rest of the team is rocking their Armani suits. If you don't ask, you'll never know, so don't be shy. It's also a good idea to visit your new employer's website and see if there are any workplace pictures from outings or events.
Quick Tips To Help You OutIf you are unsure and you haven't asked what the official dress code is then I suggest you look at a range of things to help yourself out in the first phase of your new job. The first idea is to rather dress up than down. You can always remove a tie, untuck a shirt and take off a jacket if your first week is less formal than you thought. It's nearly impossible to dress up a pair of shorts, flip-flops and a flat peak cap in the face of pinstripe suits and pointy shoes. The next thing you can do is pitch yourself in between formal and beach-wear. Going with a dressed up denim look is going to work wonders. You can wear a pair of brogues with your washed blue denims, a brown belt and collared shirt and jacket. This way you're in the middle.
Basic Wardrobe AdditionsIf you're planning on spending a bit of money to shake up your wardrobe before you start your new job then here are a few items you'd do well to purchase: In winter you're going to need a pretty decent button up jacket, like a trench coat. It should be longer and sturdier than your regular blazer or smoking jacket. It's always a good idea to go with a neutral colour like grey - this will allow you to wear a t-shirt, collared shirt or formal getup with the jacket and let the jacket dress up the outfit.
A basic, well-fitted collared shirt is a must. You only need a couple new ones that you can mix and match. Go with basic patterns and colours. In fact it's always worth having at least two crisp, well-fitted white collared shirts. They can be used and reused in many different combinations.I personally prefer a good pair of denims over a pair of chinos. It's best to have denims that aren't baggy but aren't too skinny either - no one wants to see your package in the workplace.