我在用JMail开发一个邮件发送系统，但是我每次发送出去的邮件都被对方列为垃圾邮件。有的信箱就始终无法收到信件。求助大虾，如何能够避免邮件被列为垃圾邮件呢？

　　　　　jmail.MessageClass EmailMessage = new jmail.MessageClass();
                EmailMessage.From = "×××××××@126.com";
                EmailMessage.FromName = "××××";
                string[] to = this.tbto.Text.Split(';');
                string[] cc = this.tbcc.Text.Split(';');
                EmailMessage.Body = this.message.Text;               
                EmailMessage.Subject = "JMial程序设计";
                EmailMessage.Charset = "GB2312";
                if (this.tbAttachment.Text != "")
                {
                    EmailMessage.AddAttachment(this.tbAttachment.Text, false, "");
                }
                for (int i = 0; i < to.Length; i++)
                {
                    if (to[i] != null && to[i] != "")
                    {
                        EmailMessage.AddRecipient(to[i], "", "");
                    }
                }

                for (int i = 0; i < cc.Length; i++)
                {
                    if (cc[i] != null && cc[i] != "")
                    {
                        EmailMessage.AddRecipientCC(cc[i], "", "");
                    }
                }
                EmailMessage.Send("smtp.126.com", true);