Be responsible! Go on age appropriate websites that are certified safe by Norton, Kaspersky etc to make sure there are no malicious items on the website.
2).
Don't share private information to anyone. If you do you can be easily hacked and they can take all you private information like credit cards, phone numbers, house address and paypal accounts
3).
Buy a virus protection plan, from Norton, Kaspersky etc. They do cost quite a bit but it protects you and your computer from spyware, viruses etc.
4).
Make sure you know your social media settings, set your settings to private so only your friends and family can see what you post, not random strangers.