I would love to join the Review Revolution; but there are so many fanfics and so little time :) -- even within my own currently-favored HP "Fremione" pairing stories. When I *Do* review, however, I'm usually thorough, giving concrit on more than one aspect of writing; and try to always end my comments on a positive note of encouragement. My goal is never to discourage anyone from their writing, but rather to help make their stories better.
Common Recurring Spelling/Word Usage Errors on Fanfiction.net
Is Your Writing Plagued By Any of These Homophone "Gremlins"? (Hint: They're not often caught by spell-check software; and can have quite different meanings!). The first is most often what is written; while the second is what is actually meant (the correct term):
quite vs. quiet
Other than just general grammatical Confundus-isms, there is also a prevalent tendency to incorrectly render proper nouns and Wizarding terms specific to the Harry Potter 'verse -- even those which are frequently recurring. I was considering compiling a custom list, when lo and behold I discovered that (somewhat to my chagrin) that particular proverbial wheel had already been invented! (Or at least basically. Personally I think I'd probably have formatted it somewhat differently). :) Not sure whether "Apparate" is spelled with three "A"s or two "E"s; or if "Quidditch" has a capital "Q" or lowercase? Click here for help at a glance:
An alphabetical list compiled by Sycophant Hex's admins of canon words. While I don't think this has been updated recently, this shows both US and British renditions of canon terms, and spans all the HP books current as of April, 2006.
Another helpful link:
There are several things one can do to avoid the above mistakes (and others). Firstly, don't try to multitask when writing! (or proofreading). Turn the TV off, keep the radio on low (if at all); tell your friends you'll call them back (or continue texting) later; log out of World of Warcraft, etc. And for heavens' sake, don't try to write while simultaneously doing homework, or taking notes for a class lecture (no matter how boring)! Eliminate those distractions -- give your story (and your characters) your clear undivided attention. If a tale is worth creating, it's worth writing well. Your finished product will be much better for it. Usually when a writer acknowledges something like, "I wrote this in 20 minutes during world history class..." in their A/N, it shows.
Secondly, when proofreading, go slowly. It is easy to miss errors when you're reading something for the umpteenth time and know practically by heart what exactly you intended to write; so that you accidentally misread it into the text in place of what is actually there. To encourage yourself to slow down, try reading your story backwards; or print it out before rereading it. Somehow it's easier to catch things in print than when reading a monitor screen. Reading your story out loud helps, too. If it's late (and you're tired), sleep on it -- then come back and edit when your concentration is fresh. If you don't have a beta reviewer on Fanfiction.net, ask a friend to read it over and get their input.