I think helping you to put a motivation plan is difficult some how. I should know first the type of your organization, and what made you think to put such a plan in the first place? Was there a high turnover? do you feel that employees don't work properly or there is a lack of enthusiasm.
Any way, there are some ideas that may help you:
1-try to give rewards for best performance
2- you should inhance communication among management and employees
3- suggest a plan for entertainment(summer resorts, open meetings ...)
4- develop ways channels through which employess can express their grievances, that may help them feel justice is there.
5- promotions and financial raises are very inportant as well.
I hope you can get use of these ideas, and good luck.