Phew! You have FINALLY hired someone for that open position. Think about how long tha took. How many resumes you screened, how many interviews you had, and YES! Finally - a good candidate! Everyone is excited for the new person to start. People have been waiting months. Now don't blow it!
Onboarding is THE MOST IMPORTANT thing for a new employee. I can't stress this enough. Screw up a new employee's first few days, and they won't come back. Make sure your new colleague meets everyone. Make sure they have a working computer. At the very least, make sure someone takes them to lunch! You are all so thrilled to have this person, don't let the excitement fizzle out on the first day, your new teammate doesn't know that you are excited if you ignore them.