Question about Outlook Express

We are Jobzella.com Company, A professional Network for Jobs and Careers. Our Registered Users who are using Mails on Microsoft ( Hotmail or Outlook) are facing problems to receive email from our servers as It always goes to junk folder

 

We would like to know how to avoid this and deliver our Mails to inbox

 

Is there is a Guide or requirements we need to follow ?

 

thanks