Dear Gsubarathina,
Hi! I am glad you thought about it. That itself means the start of the celebration. I would say gather all your colleagues, both male and female, and tell everyone the importance of the day! Women are now as important as any other efficient men. You could emphasize on "No gender bias" and "no glass ceiling syndrome" for women. I believe we all should strive hard to cooperate with women, whether spouses, mothers, sisters, or colleagues, but then women should also make an effort to understand the men and try to get along with their needs.
As far as the celebration is concerned, you could always choose "Woman of the month or year," telling others about her strengths from which they can learn. You could mention her strengths loudly in front of all and gift her some flowers or any present, along with some food for others gathered. You could include a small cake for all your employees with "Happy Women's Day" written over it. All these things would motivate your female employees.
Later on, you could discuss the weaknesses of the particular chosen "Miss Woman" to her only on a one-to-one basis some other day and let her know that she should improve upon those areas. Hope you find it worthwhile.
Take care.
Best wishes, Harsh