Proofreading and editing, waterproof ideas?

With a relatively large part of my first draft finished, I was thinking of having others read it for me. Now the obvious problem with that is: who will read it for you? It's obvious that you yourself might be all passionate about your work but you might as well encounter many problems in the department of convincing others to read a work in progress. More precisely, a work in progress they must read attentively and scan for error and incoherency. So we've come on the terrain of proofreading and editing. Whereas these terms may seem relatively close in meaning, they are not the same.

Proofreading is the reading of a text to spot errors of a technical nature. Grammar mistakes, double words, wrong punctuation and so on.

Editing is the reading of the text on a more narrative basis. You try to find incoherency in dialogue, events, flaws in character build-up. All for the benefit of the quality of the story itself.

Prooffreading, finding the errors in other people's texts.

The problem, however, is where to find those people motivated enough to read your unfinished material. Obvious resource #1 friends and family

Friends and family will most likely comply to reading your story, unless they politely decline of course (be prepared for this). Understand as well that people might be a bit hesitant to tell you the full truth because they don't want to hurt you. An unfinished story is a very personal thing after all.

Source #2 professional companies
Professional proofreaders are abundant. http://www.proof-reading.com/ for example. It's not too expensive and you're assured of quality. A lot of universities have their own proofreading facilities as well.

Source #3 teachers and students of languages
Very close to #2 but if you have personal relationships with these people, things get easier. When you're still a school-goer you can simply ask your teacher to do it for you in his/her spare time. Just hope you're on good footing with that person though.

Source #4 writing communities
Examples such as http://www.nanowrimo.org/ and other writing communities are full of people writing, interested in writing and readers. You can try to find people here if you need a proofreader/editor. Be cautious about throwing your story out in the open though. Read up about copyright before spilling the beans.