You can save a site as a template at any time using the template option (Save site as template) on the Site Settings page in SharePoint. SharePoint Designer 2010 make it easy by providing a Save as Template option in the ribbon, which takes you to this page in SharePoint. Once you save the template, a solution file is created and stored in the Solution Gallery where you can download or activate the solution.
To save your site as a template using SharePoint Designer 2010, perform the following steps:
1. Open your site in SharePoint Designer 2010.
2. On the Site tab, in the Manage group, click Save as Template
3.This takes you to the Save as Template page in SharePoint.
4. Specify a name to use for the template file in the File name field.
4. Specify a name to use for the template file in the File name field.
5. Specify a name and description for the template in the Template name and Template description fields.
6. To include the content of the site in the site template, check the Include Content box.
Note: Including the content of the site can increase the size of the template significantly. Keep in mind that the default size limit for a site template is 50 MB but may be less in your organization.
7. Click OK to save the template.
8. If all of the components on the site are valid, the template is built, and you see a message that says Operation Completed Successfully.
9. To download or activate the solution from the solution gallery, click the user solution gallery link and follow the steps in the procedure below.
10. Or, to return to your site, click OK.