I have a friend who is always helping others but won't accept help from others
You could point out that the pleasure she gets from helping others is something she should allow others to feel as well by helping her (in that way she's actually giving them something by allowing them to help her). But good luck with this one. Some people dont like accepting help. It makes them feel vulnerable and dependent on others. I know because I never ask for help. Also, you could frame it in a different way, instead of using the word 'help'. But honestly, I dont know if there's much you can do. You're talking about changing a person's entire way of looking at things. Unless she wants to change, you cant do anything about it. Another way is to simply do something without asking. Like my friend's mom would make me food when I was sick. Now I never asked for it, and if she'd offered, I would have said no. But I mean there's not much I could do when my friend was standing at my door with food made for me.
Let him or her know that them accepting help doesnt make them a weak person and that no one with think of them like that. A lot of people feel like accepting help is like admitting they cant do things on their own. Everyon could use a hand every now and then, make sure he or she knows that. :)
***will not with. -.-