A good summary has three basic characteristics: conciseness, accuracy, and objectivity.
Accuracy is one of the main characteristics you should remember when writing a summary to ensure that your text is correct or exact to the original material.
Concise writing is clear and does not include unnecessary or unclear words or language. Conciseness and clarity are very important in your writing. It makes your text easily understood by the reader.
Objectivity, in summary, mean you should not include any opinions or judgments about what is in the original text. You write the information in your own words. But it should only include information that comes from the text.
If you follow these three tips I guarantee you will get a better grade on your next summary writing. Good luck!