What should be included in a summary

A summary should include key points from what you have read or learned. Basically meaning that you should include the main idea, basic ideas, and other small points as well. When making a summary there is no need to include ALL of the original piece but just key points as explained before. So to make it easier I will write everything down into a list.

Include a thesis (explain what the text was trying to achieve)
Include the topic sentence
Include key points (main points and phrases)
Include major supporting points
Include explanations
Include your a concluding sentence as well
Include any extra information that you feel should be added.

This should be able to help you write a summary. If you feel that there is something missing you can always google it but anyways these points should give you an idea as to what needs to be in a summary.

Hope this helps!