There are few common types of errors - look for them and correct if necessary. 
1. error in subject-verb agreement, for example she eat
2. errors in verb tense, for example Yesterday I will go to school.
3. error in verb forms, for example I will driven home.
4. errors in word forms, for example I am quite confusing.
5. errors in structure of the sentence
6. improper choice of words
7. improper prepositions