How do I block certain people from viewing things I post on my facebook wall?

[Kally]

If your talking about hiding certain posts from certain people that you've posted in the past, what you do is you find the post, Look under your name on that post, Find the date on that post and click on the icon right next to it when you scroll over it it should become a drop-down bar, click the drop-down bar "Friends" click on "Custom" and type the names of people you dont want to see this status post.

Or...

When you post something you can click on the drop-down bar "Friends" click on "Custom" and type the names of people you dont want to see this status post.