While companies and celebrities are happy to gather as many Twitter followers as possible, some folks elect to have a private page. When a user has protected her tweets, you must send a request to become a follower. The process is easy and takes just the click of your mouse. Once your request is sent and the user approves it, her tweets will immediately begin to show up in your news feed.
Find a user by entering her name or Twitter username in the "Search" field at the top of the Twitter home page.
Click once on her name in the search results.
Click the white "Send Follow Request" icon under the user's thumbnail image and username. The Twitter user is sent a message that you want to follow her, and she will either grant or deny you permission to see her tweets.