The best time to enroll employees is at new employee orientation, when employees become eligible for an employer match and when they receive an automatic employer contribution.

Round table discussions are great ways to foster positive group behavior, she said. Once you get people nodding that they are in charge of their retirement future, they are more likely to fill out an easy-enroll card.

Tell younger employees that their retirement plan and employer match is part of their overall compensation. That usually gets their attention.

Companies also should target their message to older employees who believe saving is a pain. Tell them that working until age 82 is much worse.

The presenter should be positive and give the impression that he or she expects all of the people in the room to enroll in the retirement plan. If someone decides not to enroll, they should be required to fill out the easy-enroll card anyway. They can write a zero in the contribution section and sign their name. "Sometimes just having to document that they were offered a benefit—that they declined—is enough to get them to change their mind and enroll," the report said.

Education is still important, so schedule an one-on-one session with employees that sign up so they can have a trusted friend or family member along to help them decide what to do.

If your plan has automatic enrollment, use easy-increase cards instead. This allows them to increase their contribution rate automatically every year.  Tell employees what the average participant deferral rate is. People are competitive and will want to defer the same amount as their peers.

Diversified provides customized retirement plan administration, participant communication and open architecture investment solutions for mid- to large-sized organizations.