Make daily back-ups of your important data
Regular back-ups consist of making a copy of all the important data on a (non-)physical carrier, which is different from that on which the data was generated.
Making regular and comprehensive back-ups of data is the only good assurance against an infection or an attack that would corrupt the production data or render it inaccessible. Data restoration tests show the resilience and capacity to roll back to a healthy situation.
Advise your staff to make back-ups, or set up a system to do this automatically.
Regularly check that your back-ups are still being made every day and are recoverable.