Please, for the love of God, do not give her unsolicited advice. I promise you she's heard all your "tips" before and probably tried plenty of them. No matter how kindly you offer it or how helpful you think you're being, there's a very good chance it will come across as condescending and like you're trying to fix her because she isn't good enough as she is. That's kinda how even this post comes across a little bit - I know you mean well but are you a speech pathologist, a covert stutterer yourself, a sibling of a stutterer even? If not, then what makes you think you can offer any "tips" that she hasn't heard before? ASK her what would help if she seems upset about not being able to talk to your friends or whatever. Stutterers are all different, what helps one person another might hate.