Twitter has a great help page that shows you how to customize your Twitter experience.
Once here, go to ‘The Basics’ menu on the left side of the page and click on ‘Customizing your experience’:
It is helpful to go through each of these menus to understand the differences between protected and unprotected tweets, as well as how to be able to approve your followers. Another helpful page is their Safety & Security tips:
Pay special attention to the ‘Protecting your personal information’ page as it has detailed steps about how to protect your personal information in your account, how to have your personal information removed if someone else posts it and keeping your account secure. One particular page to note is how to turn off tagging for pictures that you post:
This will help ensure that information tied to your photos is not inadvertently made public.