When people ask for critique and beta readers, it's always different. What you have to give is an honest, unbiased critique that tells the writer that they can work on and what they are good at. Sometimes you will get the writer who wants the "I love it, keep going!" and nothing else critique. That's fine and you can give it to them, but if you really want to help them, give them a real critique. I have never had a beta reader for anything, but my dream beta is someone who is honest and will tell me what I need to work on/suck at, but won't berate me because of it. A person who is honest and tough, but will always encourage me to be more specific! To get more out of the author, ask them if they want it soft or brutally honest. if they give little details of what they want, ask them and few questions. If they give you nothing more, give your best critique and if they get mad because it wasn't what they wanted, there's nothing you can do. I hope this helps!