think, "what advice would someone who wants to help me offer in this scenario?"
Its as easy as just STANDING UP FOR YOURSELF
It goes with the territory. I suggest you get used to it. But the good people you meet along the way more than make up for it.
Unfortunatly the world is full of 'takers'... you have to learn how to say NO... take heed of your heart and you can still help those you think need it... good luck.
If you truly wanted to help others, you wouldn't care about protecting yourself. What's the worst that can happen when you get "taken advantage of"? Your ego gets bruised? What ego? Was it ego that caused you to want to help them in the first place? Or do you just feel used afterwards? Wasn't that the point to begin with: to be used?
If your offer for help is contingent on never being taken advantage of, then your help is conditional and you are looking for a guarantee. It is in your mind - even while you are helping - that you may be taken advantage of. The thought makes you either angry or fearful, or both.
Where, exactly, do anger and fear come with a seemingly innocent desire to "want to help others"?
If you truly want to help, you will have to accept the fact that getting taken advantage of happens even to the ridiculous people who go around with "shells" on and that type of nonsense. The only thing being defensive does is make you less instinctual, less compassionate and more in need of helping yourself. If you are truly free - if your help is worth anything whatsoever - you will not worry about this nonsense, and merely continue helping.
Only the ego plays these types of games.
What a wonderful question, and unfortunately I have no answer, but suffer from that same problem. I have come to realize that if you are out there to help there will always be someone there to take, with or without really being genuinely appreciative of it. Good luck. I mean the only thing I have actually thought would cure that problem is to not help people anymore, but I really can't bring myself to do that!
Grow a hard outer shell. You can still help others all you like, but it'll hurt less if someone takes advantage of you.