Your kid has now learnt to emote and understand feelings. She has started school and has made friends. You now need to teach her how to handle relationships.
What you can do
A kind person can tackle any situation and you must teach your kid to develop this characteristic. Kindness begins at home and it must be taken seriously. At this highly impressionable age children tend to grasp ill habits and behaviour quickly. You should demonstrate acts of kindness so that the little one can learn from it.
Help the elders and other members of the family in different tasks. Offer the needy people food and clothing. These acts would motivate your child to also develop a soft heart towards other people. Teach her to share her food with her friends in school. If something goes wrong and her classmates behave in a rude manner then ask her not to turn aggressive but respond in a calm way. These lessons are very important and would prove helpful for the child to grow into a better person.