Pointers to Identifying Errors

1. Parts of speech
2. Punctuation marks (;,.,",',!)
3. Voice of Verb (passive, active)
4. Subject Verb Agreement 
5. Spelling
6. Tense (past, present, future, etc.)
7. Contradictions
8. Antecedents
9. Degree of comparisons (positive, comparative, superlative)
10. D-Verbs (do, does, did)
11. Conditional sentence
12. Moods