As writers it’s necessary for us to proof our work and find grammatical errors and any inconsistencies. It seems easy but we always seem to miss something. That’s why it’s great to have a critique group to help.
If you think that proof reading is an easy task take the test. The Society For Editors and Proofreaders has a test to check your skill set. Visit their site and see how easy or hard it really is. Let me know your score.