By doing things for others you are not allowing them to do for themselves. You are creating a co-dependant relationship. You are taking on
their responsibility. Do you believe that they honestly can't do anything without you?
Try thinking to yourself that by coming and asking you for all this help, they are actually being lazy. They don't want to do for themselves, they want you to do it all for them. As a teacher, what advice would you give them under this light? As a teacher, how would you teach them to support themselves in these situations?
Just an example for your second scenario...
I really think it will help your technique to play with others, take what we have gone through in this round and try it with other players... see how it works for you.
You would not exactly be saying no in this above example, you are giving them the opportunity to take what they have learnt and use it themselves. Initially they will probably be insecure with this idea but if they don't seek the confidence to do it themselves, then why the heck do they want to do it at all!