Plan people's access. There is no point in giving cleaners 24-hour access to the offices. Allocate passes and keys that are tailored to people's needs.
Get your team on board. Ask your people how safe they feel, and what you might do to improve things. Swipe cards can lead to fears about Big Brother surveillance, so explain your reasons before you introduce them.
Keep it friendly. Have people on the front desk with a bit of character and the knack of remembering people's names. They will reflect far better on your company than monosyllabic thugs.
Stop the piggy-backers. Having to show their pass every time they arrive at the office can be a bore for staff, but it is the best way of ensuring that no undesirables enter. Encourage your team to report loiterers and unfamiliar faces lurking around the entrance.
Let there be light. Simply fitting floodlights will make the shady corners in your car park that much more friendly and safe for late leavers.
Give yourself time. Be diligent. Don't let your team encourage crime through laziness or carelessness. Ensure doors and windows are checked at night, and tell people not to leave valuables near open windows.