About two years ago, the Harvard Business Review ran an article entitled "Why Email Marketing is King." Essentially, the author wrote that email is king because it is measurable, relatively easy and the most cost-effective way to reach your customers and prospects.

No wonder most marketing pros try to convince you to use social media, advertising or some other costly media. It's tough for them to make any money on you if you are effectively leveraging email.

But email can be an effective marketing method if done properly. Here are a few time-tested email marketing strategies that successful senders have used to get their emails opened and read:

1. What is the best time of the day to send an email? In its quarterly email report for 2012's fourth quarter, Experian, the global information services company, found that "the time of day that received the best open rate was 8 p.m. to midnight." This time range not only performed better for open rates (a respectable 22 percent) but also for click-throughs.

Other industry experts recommend the second half of the business day as the best time to reach the most readers. I would bet that it has a lot to do with the person receiving the email. If I am a driver for UPS, chances are the best time is in the evening. If I work from home or in an office, I probably get a chance to review my email during the day. Since you generally won't know the circumstances of the recipient, I would suggest sending emails toward the end of the business day or on the weekends, which was Experian's second choice.

2. Keep the subject line short. If you want your email opened, give the recipient enough to make them curious but not so much that they decide to delete the message. The Obama campaign really showed the amazing strength of short titles during the 2012 presidential cycle. They often used just one or two words, such as "Wow" or "Hey." The campaign experienced incredible read and response rates, and many felt its use of email was a major contributor to Obama winning a second term.

3. Mobile is queen. Think chess. The queen is the most mobile and powerful piece on the board. It's the same for mobile devices, where fully half of all emails are now opened. If your emails do not play well on mobile devices, you are not leveraging your queen. So if you just spent $10,000 on an email campaign and did not pay sharp attention to how it rendered on mobile devices, you tossed away $5,000 right off the top.

4. Email still reigns over Facebook and Twitter. Social media may have all the buzz, but email, the content king of the inbox, still holds sway in social influence. Over an 18-month period, SocialTwist, a customer acquisition and retention platform that generates referrals for businesses, monitored 119 referral campaigns from leading brands and companies. The results showed a significant advantage to email's ability to convert new customers compared to Facebook and Twitter. Of the 300,000 referrals who became new customers, 50.8 percent were reached by email, compared to 26.8 percent for Twitter and 22 percent for Facebook.

I have been involved with B2B and B2C marketing for more than 30 years. (That's before email, for those keeping score at home.) And in that time, it has become crystal clear to me that the number one reason, by far, why small businesses fail to meet their marketing goals is that they do not execute consistently on the plan they put in place.

Do not feel bad about it. Executing on a proper marketing and email campaign takes a lot of time and coordination. So here is the real tip: Hire a professional who is focused entirely on what you want to accomplish. This is someone who can take the complex task of recruiting new members and maximizing your existing members to new heights.

Good luck! No, let me rephrase that: Do not count on luck. Hire a professional for the best long-term results. Your members do it every day.

Content Sponsored by Motionsoft.

Robert Skinner is the executive vice president of sales and marketing at Motionsoft. Robert has more than 30 years of senior management experience in private and publicly traded software companies. Most recently, he was CEO of Agentek, a provider of field service mobile solutions. He also has served as vice president of sales and marketing for the MRM division of Trimble Mobile Solutions and was executive vice president of sales, marketing and professional services at Vastera Inc., a publicly traded global trade management software company that was acquired by JP Morgan.