For example, a student wrote of Lear and Cordelia that their bond is "mutual." A bond between two people can only be mutual. Another example is the description "He wore a hat on his head." There is no need to mention that the hat is on his head; one can assume that he would wear it there. Be aware of the implications of words to avoid redundant observations.
Another common redundancy is the use of synonyms. Students feel that they need to produce lists instead of single words, and thus write sentences like "If you own or possess something of value." "Own" and "possess" are virtually the same word, so using both is redundant.