Learn lots of Story books and the topic on which you are going to write the summary, you should be sure to read and get as much information from the topic so that you can write a very good summary. Take help from guide books but do not copy the whole thing from the guide book. If your paragraph is too long, make parts of it and make it like an essay. For me, my father encouraged me to learn story books and told me they will make my English strong and this worked for me.
Hope this helps you too:)