At the interview stage, where possible, you should explain how the role they will be undertaking fits in with the business vision and long term plan. When a job is offered, again, reiterate how important their role will be to the team and department that they will be working in. This will create a real sense of solidarity from the get-go.
Prior to their first day, provide all relevant logistical information to ensure things run smoothly. Provide directions and car parking information; inform them of dress code and who they will need to ask for on arrival and where to go. Request all relevant paperwork to be ready for their first day. It may prove beneficial appointing your new employee to start an hour after everyone else on their first day, in order to prepare and set up their desk. Be sure to provide all relevant stationery, computer logins and passwords, contact lists, business cards, map and employee handbook as well as their contract of employment.