It's easy to burn out a motor by dropping unopened envelopes and junk mail into the shredder, which may contain more paper than the shredder can handle.
For household safety, make sure to unplug the shredder and place it out of reach of children and pets when you are not using it.
Make sure to keep the wastebasket empty. For a shredder to work efficiently, the shredded paper needs to be able to drop freely into the wastebasket below.