don't add people that you don't know and make sure all of your social media profiles are set to private so only your friends can see your things that you put up not friends of friends or strangers
If someone is doing some one is doing something that is upsetting you the best person to talk to is someone that you trust. Whether this is a good friend, a teacher, or someone that you live with.
If you are being cyber bullied or being made to do things that you don't want to do REPORT ABUSE! do it here: http://www.ceop.police.uk/Safer-By-Design/safety-centre/
The creator of this guide has not included tools