First of all, it's crucial that you know exactly who you are looking for. Without that knowledge, it's going to be hard to find that right investor.
How is investing in your competition? Who would be your dream investor? What are the values your ideal investor has to represent? How much capital do you want to raise?
Once you have questions like that figured out, it's much easier to determine where the right investors hang out.
LinkedIn is one of the best places to connect with investors from my experience. LinkedIn groups are a great place to start making connections.
When it comes to "who is right and who is not?", the quick answer is "Listen to your gut".