Summarize the following:
Ask her how she would like your relationship to change. She might have some great ideas in addition to the ones you’ve already considered. Make sure that you have this conversation in private and with plenty of time to talk. Find something that you both enjoy doing and make time to do it with her. Sometimes it’s hard to find common interests, and it might be fun for you to try something new together and see if you both like it (or both hate it).  Go to a movie Watch TV series Learn how to kayak Take a cooking class together Explore a new neighborhood Try a new restaurant A lot of siblings find that short texts and Facebook posts help keep them close, rather than lots of long conversations. Once you and your sister have established a strong relationship, keep it up through shorter, casual contact with long conversations every so often.

Summary:
Tell her you want to make time to be a better sister. Do activities together. Keep in touch.