I think the best places to meet the kind of people you can make these relationships with are probably in English classes or at writing conventions. If these aren't available to you, there are a lot of writing groups online (I belong to one: Obscurity Knocks) in which you can post works and receive feedback, and one benefit of these groups is that you don't necessarily know that people who are reading your work, and then you can be really honest.
Another good way to meet people is by starting a blog and reading other blogs. Since I've started this blog, I have discovered a lot of other writing blogs that I enjoy, specifically Creative Writing Corner and Writing Forward. If you engage in coversation with other writing bloggers, you'll fine a great group of people who are willing to read and comment on your work.
The benefits of having a writing circle, rather than reading and editing a whole project on your own are so numerous, it seems ridiculous to try writing without that circle. I'll just expound on a few of my favorite benefits:
- Having a different angle on your work. I was working on a screenplay last winter, and I got to a point where I couldn't decide whether to kill a certain character or not, so I called up one of my handy writer friends who had read a majority of the screenplay and asked him what he thought. He asked all the right questions: what would the other characters do without her? What could she add to the plot if she stayed alive? How would she die? and many other aspects I had not yet considered. I was then able to continue writing with the whole picture in mind.
- Discovering weaknesses that you didn't see yourself. I sent an excerpt of a novel to the same writer friend, and his feedback shocked me. The bad guy didn't really seem bad. This excerpt was supposed to be a scene where the villian's pure evil nature shrouded the reader in darkness. But it didn't do that for my friend (perhaps he is accustomed to evil?). He gave me suggestions, mainly pertaining to the rhetoric of the villian's dialogue and mannerisms, on how to make the villian feel more evil.
- Bouncing unstable ideas around. I've been considering a certain project for quite some time, but haven't been sure how to go about it. I've written a segment of what I imagine the project would be, and I've shared it with numerous people in an effort to see both how it is received and how I could expand it. Getting feedback on a budding project can sometimes be the life support that brings a project to fruition.