Lots of offices have "unspoken etiquette" rules that you will need to identify as quickly as possible in order to slip smoothly and effectively into a routine in a new job. Sometimes the rules may not be crystal clear and you may have to look hard in order to avoid offending someone with whom you work or creating an unintended conflict. Being able to identify "unspoken etiquette" is as much about being courteous and asking the right questions as reading the office rule book, so be prepared to be polite and be corrected along the way.
One of the biggest issues in office etiquette that may go unaddressed is, surprisingly, the dress code. Most offices do have some formal dress code, but generally you should err on the side of conservatism, particularly at first, rather than walking the fine line between appropriate and inappropriate. Add a few inches on skirts past the bare minimum and keep decolletage largely covered, particularly if you are well endowed, until you have seen how other people with similar body types to yours dress in the office and observed office mates' reactions and behaviors around them.
Next, be aware of simple things, like allergies. Most offices have no problem with air fresheners or even candles, though the majority do prohibit incense. However, if the guy in the office next door has asthma or allergies, it might be considerate to find out how those items will impact his ability to breath. And frankly, strong scents make many people nauseous. Even if no one is actually allergic, you might want to think twice before putting in something the aroma of which will not be entirely contained in your office.Finally (and this is the big one) fish and popcorn. You're probably thinking, "What?!" but these are huge office "no-no's." They both stink up the entire workplace with a pervasive and not universally pleasant smell that can take days to dissipate. So leave these two food items at home, or prepare them ahead of time, so that you do not stink up the kitchen for everyone. (Cabbage, while far less popular, is also pretty smelly when microwaved and should be avoided). Keeping your eye out and your ears alert can help you stay on top of things at your office and keep all your co-workers happy.