Domain Social Forums

Would like to know all possible way to make my WordPress site secure from hackers.
Are there any experts who can share their tips here?

One of my co-workers shared these ones:

• Create WordPress Sites on FLATsite
  
• Use TLS or SSL Certificates
  
• Utilize DDOS Protection
  
• Implement a Website Back-up
  

Have you tried FLATsite static wordpress site generator? Is it really good solution?
So, could you share your view points on securing wordpress site from hackers?

Thanks.