Your parcel is securely packaged when each item is wrapped separately and there is protective and shock-absorbing material between the individual items and the outer packaging. The contents must lie firmly and securely in the package and must not bump into each other.
Items with liquid goods should always be placed in a plastic bag that is sealed before being wrapped in protective material.
Electronics should always be wrapped in a minimum of three layers of bubble wrap if you don't have the original molded inner packaging.