Dear Anjali,
1. How do we create a common culture in an organization
Culture forms up in an organisatoin based on the values, attitudes, customs, traditions, experiences, and beliefs of most of the members. For creating a common culture, you first need to find out which values, ethics, beliefs and attitude are more dominant than others. If the dominating ones are also positive ones, then you can popularise them further. But, if those are negative ones, then you need to take up corrective steps. For example, if as a value the employees display examples of 'Trust' then shortlist it. But if they do not show trust on others, then your job will be to create awareness on this issue. Such shortlisting will give you a fair idea what kind of a culture your organisation have and how you can add further value to it.
2. What roles value play in formulating a culture
Perhaps the most important. A culture of an organisation is weaved around the values it follows. If an organisation values 'openness' (i.e., accepting and allowing mistakes) then the employees will work freely. On the other hand, if mistakes are not tolerated, then the employees will fear to accept mistakes and will blame others to cover their skin.
3. Can values by themself create a culture
Yes, they can. [ref. ans. to your previous question]
4. What are the elements of culture
These are Values, Beliefs, Customs, Traditions, Attitude, Mindset etc.
5. How to create a common culture across geographies
If you are talking about multi-locational units, then it will be a challenge to create a common culture, because Culture is also influenced by the geographical customs and traditions. You cannot make it a culture to allow people wear bermudas in office in Pakistan whereas it is absolutely fine in US.
However, by constant publicity of the elements through various modes, viz., training, posters, emails, sms, informal talks, citing examples, making/revising policies that'd suit the culture, etc. you can have some commanility of culture across geographies.
These are my thoughts. Hope you'll get some idea.
Prashant