If you have no restrictive covenants in your employment contracts or if your idea of restrictive covenants is to take a standard approach, it could be worthwhile having them checked by an employment law specialist. It is possible to change the contracts to protect your business, provided you consult properly with your employees, take the correct approach and comply with the relevant employment law.
You should also consider carefully how you protect your confidential information, such as customer and client lists. This will, to some extent, depend on the nature of your business and what practical measures are possible. At the very least it should be relatively simple to adjust your IT system so it can log when, and by whom data has been accessed. You could go much further and block up USB ports, remove all floppy disks and CD drives and control what is printed, but this may well be impractical, although we did have an employment law client who did this. Overall, you may want to consider some form of employee monitoring but you should be very careful that you preserve the goodwill of your employees - the best cure is prevention and so long as you retain your employees you will not need to rely on the restrictive covenants.