There are no fixed rules about how a person should behave in office but keeping a few basic points about office etiquette in mind always helps. A smile can brighten up someone's day and everyone appreciates being greeted pleasantly Always return phone calls promptly. When people leave a message, they generally need to speak to you importantly. And nobody likes waiting or calling up again and again to check if you are there. Be punctual for meetings and don't leave early.
Punctuality always makes a good impression.
And leaving early is considered very rude especially if a person is speaking or giving a presentation. Always dress according to the environment in your office. If people follow a casual dress code in your office, you may make them uncomfortable by turning up in formals and casual wear will definitely not be appreciated in a formal environment. Whether the dress code is formal or casual, always dress neatly. Keep your word.