I took a test for being a proofreader at ExpertRating.com today. Passed it with a score of 62 out of 100, which is at the 94th percentile of all test takers. Here are my partial scores:
grammar & usage, 89%
number usage, 50%
proofreading for consistency and accuracy, 70%
Now I will look for a proofreading job. These could be either freelance or physical office jobs. I understand a typical pay rate is $18/hour.