These are tips to keep your information and photos more private on Instagram
1) Make your Instagram profile and photos private. This will prevent the general public from finding you or your photos. Details on how to complete these steps can be found HERE keeping in mind when photos are shared across multiple social media sites they can all tie back to each other so be careful.
2) Block anyone who is currently following you that you feel is inappropriate or Unblock someone whom you have Blocked by accident by following the steps HERE
3) Learn How to Address Instagram Abuse HERE that link includes contacting law enforcement should it be deemed necessary.