There are three pieces of Private Identifying Information thieves want:
Do you have a nick name? Use it on social media rather than your legal name.
If you don’t need to give your actual birth date, but they site needs one. Then give a fake date.
Your Social Security Number
Ask why do you need my Social Security Number? Most companies who ask for it don’t need it. Your doctor doesn’t need it.
Don’t give it, if you don’t need to.