I check out the tweets to or about Sam and then I show the tweets to her that I think are appropriate and we talk about them. Then I ask her if she wants to reply or retweet and she tells me what she wants to say and I type it in for her.

I think it works because there is some content on twitter that is a bit too mature for her and I can screen that. Also, Sam is only nine so she sometimes does not understand certain tweets so I can discuss that with her.