I have seen that most of the time, sharepoint professionals are facing hard time to deal with master page and branding in sharepoint. So, I have decided to write easy ways to deal with master pages. Here is my first blog over sharepoint branding. Please do the following steps to create a master page from existing:
1. Open the site into windows explorer
2. copy and paste a master page in masterPages folder. Rename the copied one.
3. copy and rename css file from style folder(see the css path in master page's html)
4. copy all the images and paste into a new image folder(see the image path in master page's html). Change the images according to your branding.
5. change the image folder's in image's source in master page's html
6. Save checkin
Now your Master page is ready to use.
Go to the site properties and click on master page under look and feel section. select your master page for "site master page" and "system master page" .
Go back to home page of your website, you will have a new look according to your master page.
Happy Green Coding !!!