Here is some great advice from a fellow Career Coach I work with:
Time and attendance – Give yourself plenty of time in the morning to take into account trains running late, inclement weather, or other unforeseen interruptions to your daily commute. Show up 15 minutes early. Put in a full day at work.
First Impressions count – smile, firm handshake, make eye contact. Clothing: dress appropriately from what you have seen during the interview process, body language, smile, look interested. Pick your outfit and lay out your clothes the night before. Pack your things and make your lunch, so you are ready to get up, shower, eat breakfast and go.
Listen and Ask Questions – Take notes. Be open to listening to HR, to co-workers, to your supervisor. You will not be able to remember everything they tell you about attendance, Xeroxing, passwords, shared documents, health care plans etc.
Positive attitude, take initiative, volunteer – Attitude is more important than knowledge your first day. No one expects you to know where everything is or how to find the key documents. You will probably spend some time with HR filling out paperwork. You will probably be taken on a tour of the office.
Accept a lunch invitation – If you are asked out to lunch by your boss, or anyone else, don’t turn them down. Keep your lunch in the fridge and save it for another day.
For most, but not all jobs, you are not expected to hit the ground running. That is, it is expected that you will take the first few days to get to know your co-workers, learn the ropes, explore the neighborhood. Make it your priority to walk around the neighborhood and find a place for lunch, for coffee, the bank, the local pharmacy.